inline 250 integrated head upgrades [Archive] - Chevy Nova Forum

: inline 250 integrated head upgrades


Richardlss
7th-August-2007, 07:19 PM
i have a 250 inline 6 with an integrated head/intake... and i was told before that to replace the head and intake you need to get a different cam.. im not to good on these kind of modifications, but does anyone know how i could tell what kind of cam i would need for a certain kind of head... my overall plan is to just switch the 1bbl carb for a 2 bbl carb, and i cant do this with what i already have (alot of work to switch out to a 2barrel but i dont wanna go to a 4 barrel)

KEITH'S75CUSTOM
7th-August-2007, 08:52 PM
i dont think you need a new cam just use the components from the integrated head.
how are you gonna put a 2 barrel
use a 4 barrel intake and put an adapter??

Richardlss
7th-August-2007, 09:00 PM
well i was just going to replace the head, and intake manifold that is fit for a 2 barrel.. the get a 2 barrel carb. i just remember someone saying if i were to replace the head id have to replace the cam:confused:

Richardlss
7th-August-2007, 09:02 PM
Has anyone else upgraded a 250 inline 6 from a 1bbl carb to a 2 or 4 bbl? just wondered what all you had to change out to make it work... or if you know any good sites to find the parts?

KEITH'S75CUSTOM
7th-August-2007, 09:15 PM
Has anyone else upgraded a 250 inline 6 from a 1bbl carb to a 2 or 4 bbl? just wondered what all you had to change out to make it work... or if you know any good sites to find the parts?

for a 4 barrel just get a offenhauser intake, and non integrated head

KEITH'S75CUSTOM
7th-August-2007, 09:16 PM
why did you move the post up 2 spots?

I merged his two posts on the same subject into one and edited the title. ~Paul W

Richardlss
7th-August-2007, 10:05 PM
i looked on summitracing.com and found a offenhauser single plane intake, but it doesnt work for 75+ cause the integrated head... im horrible with matching pieces up, and dont understand where or how i can find a 2bbl carb to put on a intake, and the intake onto the proper head:confused:

Twisted6
7th-August-2007, 11:02 PM
In order to run a aftermarket Intake, You have to change out the
head. When and If you change out the head, YOU Do not need to change the cam. And if i remember right Some trucks That had the integrated head Had 2b carb (kinda like a holley webber)

Hit up swap meets in your area Along with any local Race track.
Esp roundy round tracks and Look for a Offey. You can run either a 4b or a 2b carb.(most offeys came as 4b But you can adapt a 2b to it)

Richardlss
7th-August-2007, 11:23 PM
In order to run a aftermarket Intake, You have to change out the
head. When and If you change out the head, YOU Do not need to change the cam. And if i remember right Some trucks That had the integrated head Had 2b carb (kinda like a holley webber)

Hit up swap meets in your area Along with any local Race track.
Esp roundy round tracks and Look for a Offey. You can run either a 4b or a 2b carb.(most offeys came as 4b But you can adapt a 2b to it)

any idea on what trucks? ill look but just to save time if you knew off hand... and i just got done reading about the cam, most of the time you can keep it original, but if you wanted high end rpms, or more torqu etc, then its good to change them...

and thank you, you did help, i had no idea about a 4b to a 2b conversion... more for me to look into thank you :)

KEITH'S75CUSTOM
8th-August-2007, 12:18 AM
yea twisted 6 is correct you need to get a non int. head and a intake.
i know the old blazers had inlines.
but the best place to look would be a salvage yard they usually have sixers out the wazoo.
oh and also you will need a different exhaust manifold for the switch.
try to find some headers if possible,

sgtsteve
8th-August-2007, 12:30 AM
yea twisted 6 is correct you need to get a non int. head and a intake.
i know the old blazers had inlines.
but the best place to look would be a salvage yard they usually have sixers out the wazoo.
oh and also you will need a different exhaust manifold for the switch.
try to find some headers if possible,


You do not need a different exhaust manifold if you buy a Offy intake, they will bolt right up to a stock exhaust manifold. I put a Offy intake on my 6, with 4 bbl and instead of going the expensive header route.....I put on a higher flowing exhasut manifold from a Chevy 292 inline. ;)

KEITH'S75CUSTOM
8th-August-2007, 01:08 AM
You do not need a different exhaust manifold if you buy a Offy intake, they will bolt right up to a stock exhaust manifold. I put a Offy intake on my 6, with 4 bbl and instead of going the expensive header route.....I put on a higher flowing exhasut manifold from a Chevy 292 inline. ;)


he has a integrated head so he will need a different exhaust manifold.




so richardlss you will need a different manifold also.
that's another reason no one like the newer sixers

the integrated the exhaust manifold bolts up to the bottom of the intake and the non integrated bolts to the side of the head.

sgtsteve
8th-August-2007, 01:25 AM
he has a integrated head so he will need a different exhaust manifold.

the integrated the exhaust manifold bolts up to the bottom of the intake and the non integrated bolts to the side of the head.

so he will need a different manifold also.
thats another reason noone like the newer sixers

Yeah, I know the difference between the two. I thought he said he was going to replace the head, and therefore could keep the stock exhaust manifold.

KEITH'S75CUSTOM
8th-August-2007, 01:31 AM
Yeah, I know the difference between the two. I thought he said he was going to replace the head, and therefore could keep the stock exhaust manifold.


i figured you did know i threw in the difference between them for anyone that didn't know why i said hed need a different manifold

the first line was in response to your post,
the 2nd and third was clarifying my previous post.

sorry for any misunderstanding
i guess i need to proof read my posts first

Richardlss
8th-August-2007, 01:36 AM
So it would be a good idea to look for older blazers in a junkyard that had a 6 in it to see if it had a integrated head/intake that came with a 2b carb?

or do you think its easier to look for a non intigrated head/intake, and buy the exhaust manifold, intake manifold, cylinder head, and 2b carb?

either option isnt bad, just which is easier to get ahold of... money isnt much of a problem, if im going to go to a 2bcarb it's probably a good idea to switch out the exhaust manifold anyways, since its stock (may be rusted out, i havent even looked at it)...

but what is Offy? is it Offenhauser? if so whats so good about them? and i looked through the offenhauser site for their catalog and i couldnt find anything for a inline 6 :(

KEITH'S75CUSTOM
8th-August-2007, 01:52 AM
offenhauser is the biggest builder of six cylinder intakes that i know of.
here is a link to some offy intakes
http://store.summitracing.com/egnsearch.asp?Ntt=offenhauser&N=700+4294822065+115+4294908399&Ntk=KeywordSearch

if money isnt that much of an issue a non integrated head offy intake with either 2 or 4 bbl carb and some headers would be the best route.

heres the reasons why.
the integrated head is not as good as the non integrated do to ithe flow and they are very prone to cracking if they get hot.(my 77 when i got it had a integrated head that was cracked in 5 of 6 holes.
cause the fan clutch went out on previous owner.

the offy intake is better flowing and is more readily availible and is the easiest way to upgrade to a bigger carb cause they were designed for it.

and the headers will give better flow and will allow you to put true dual exhaust on the car if you get the two piece headers.

i went back with a integrated head and rebuilt monojet on my 77 due to it was cheaper
it was kinda a bogged down motor for being just built and
bored
if i build another sixer it will be a 292 with 250 head and 4 barrel with headers

sgtsteve
8th-August-2007, 01:57 AM
So it would be a good idea to look for older blazers in a junkyard that had a 6 in it to see if it had a integrated head/intake that came with a 2b carb?

or do you think its easier to look for a non intigrated head/intake, and buy the exhaust manifold, intake manifold, cylinder head, and 2b carb?

either option isnt bad, just which is easier to get ahold of... money isnt much of a problem, if im going to go to a 2bcarb it's probably a good idea to switch out the exhaust manifold anyways, since its stock (may be rusted out, i havent even looked at it)...

but what is Offy? is it Offenhauser? if so whats so good about them? and i looked through the offenhauser site for their catalog and i couldnt find anything for a inline 6 :(

Yes, Offy is Offenhauser....I'd buy the other head with seperate intake/manifold. You can probably get a whole engine for under $100.
Here is one site to buy Offenhauser/Clifford parts:

http://www.merchantamerica.com/chevyhotrod6/index.php?ba=view_category&category=6089

Also JCWhitney sells Offy intakes as well....don't expect to get a deal on Ebay even though they're on there all the time. If you buy off Ebay either Clifford/Offy expect to pay in the neighborhood of $100 - $150, new ones will run around $200.


Forgot to mention also....stovebolt engine company in detroit has alot of 6 stuff.

KEITH'S75CUSTOM
8th-August-2007, 01:59 AM
or here if you want three 1 barrells:D
http://store.summitracing.com/egnsearch.asp?Ntt=offenhauser&N=700+4294822065+115+4294895572&Ntk=KeywordSearch

Twisted6
8th-August-2007, 09:00 AM
A new clifford single four barrel intake will run over 200 bucks. For used a offey or clifford I have been paying between 75.& 150 bucks.

A non integrated head Is the head of choice if you want any type of performance up grades. Especialy in the CFM
department.also Better intake up-grades and exhaust.

sgtsteve
8th-August-2007, 10:29 AM
A new clifford single four barrel intake will run over 200 bucks. For used a offey or clifford I have been paying between 75.& 150 bucks.

A non integrated head Is the head of choice if you want any type of performance up grades. Especialy in the CFM
department.also Better intake up-grades and exhaust.


Larry,

The cheapest I think I've seen the new single 4 bbl Offy intakes is around $219. Most of the used ones on Ebay go for over a $100 - $150. I picked mine up at a car parts swap meet for $65, mostly to the fact the guy didn't know what it fit. :D

Bruce
8th-August-2007, 12:29 PM
If you do not want to swap out your integral head, get in touch with Tom Langdon at Stovebolt Engine Company. He has one to two barrel adapters and will know if they will work for you. Using an adapter may cause a height issue, but Tom will likely know if it will be a problem or at least give you the measurements to make you own decision.

Richardlss
8th-August-2007, 02:18 PM
think im just going to get the non integrated head, new intake, and 2bbl if i can find one, but a 4b would do with a 2b conversion... woudl that cause any performance issues at all with the 4b to a 2b conversion?

and i didnt wanna do the 1bl to a 2b conversion... someone said your just gonna push more gas through the same size intake... which isnt bad but for more performance its best to just get an intake that supports a 2 or 4

oh and i spent most of last night at work browsing though offy website, classic industries, and summit racing and could not find a 250 intake or any that fit, most of them were for 305+... and freakin classic industries didnt have anything but cylinder head fasteners... no heads?!?! could anyone help me out, and make it alittle easier?

ok nm, just looked at the previous posts on the links to intakes with 4b carbs... what about the conversions to a 2b carb? any help finding those :)

KEITH'S75CUSTOM
8th-August-2007, 02:27 PM
ok nm, just looked at the previous posts on the links to intakes with 4b carbs... what about the conversions to a 2b carb? any help finding those :)

yeah the auto parts stores sells a plate that lets you either put a 2 bbl on 4bbl or 4bbl on 2 bbl intake.
i think they are like 10 or 15 bucks

heres a link to it at autozone (it says not availible but i know they have them cause have looked at them.) (and i know that the other stores like orielly and napa carry them also)

and a link direct to the website of supplier

http://www.autozone.com/R,NONAPP9704/store,3974/shopping/accessoryProductDetail.htm

http://go.mrgasket.com/ProductDetails.aspx?brandId=1&productID=9159540&majID=230&minID=2301&selection=6&minselection=0#

Richardlss
8th-August-2007, 02:30 PM
oh and i was looking at some of the intakes... and im not sure how to tell if these applictions will fit, http://store.summitracing.com/partdetail.asp?part=OFY%2D5999DP&view=32&N=700+115 is the one i like... but 258 is the closest it will fit, so i assume a 250 would fit as well...?

KEITH'S75CUSTOM
8th-August-2007, 02:34 PM
oh and i was looking at some of the intakes... and im not sure how to tell if these applictions will fit, http://store.summitracing.com/partdetail.asp?part=OFY%2D5999DP&view=32&N=700+115 is the one i like... but 258 is the closest it will fit, so i assume a 250 would fit as well...?

no thats mopar i believe(cause the jeeps are 258) one up the list is for a 250.
heres the link

http://store.summitracing.com/partdetail.asp?part=OFY%2D5416&autoview=sku
this is for it and 3 bucks cheaper

sgtsteve
8th-August-2007, 02:43 PM
Here's an offy for sale at JCWhitney:

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2005597/p-2005597/N-111+10214+600010934/c-10114

KEITH'S75CUSTOM
8th-August-2007, 02:47 PM
Here's an offy for sale at JCWhitney:

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2005597/p-2005597/N-111+10214+600010934/c-10114

good link and 15 bucks cheaper.

but here is a revised version of your link i put it to the exct part for him
(i mean no offense but just trying to help)

http://www.jcwhitney.com/autoparts/ItemBrowse/c-10114/s-10101/p-100000212884/mediaCode-ZX/appId-10681905/Pr-p_CATENTRY_ID:10000021288410681905

Richardlss
8th-August-2007, 04:50 PM
http://www.jcwhitney.com/autoparts/I...21288410681905 seems like the one need... thank you guys for the help, and not to be a bother, but i looked through jcwhitney to see if they had cylinder heads, it only showed 13, and none of them were for a 250... i can find a carb, but the head seems to be giving me trouble

sometimes id like to just swap the motor out for something alittle easier to find stuff for... but im a fan of the inline

sgtsteve
8th-August-2007, 05:11 PM
http://www.jcwhitney.com/autoparts/I...21288410681905 seems like the one need... thank you guys for the help, and not to be a bother, but i looked through jcwhitney to see if they had cylinder heads, it only showed 13, and none of them were for a 250... i can find a carb, but the head seems to be giving me trouble

sometimes id like to just swap the motor out for something alittle easier to find stuff for... but im a fan of the inline


There are tons of parts for these inlines, you just got to do some looking around. As far as the head goes, I would go the used route.
Like I said in my earlier post, you can find a whole engine for less than $100, sometimes even for free! You can check the classifieds on www.inliners.org, your local classifieds i.e. craigslist, or ebay. Remember, 194, 230, 250 are identical and any of those heads would work !!

KEITH'S75CUSTOM
8th-August-2007, 05:56 PM
Remember, 194, 230, 250 are identical and any of those heads would work !!

this is true but i think the compression is different if you use a 194 you might have to rebuild it, and a 230 would actually boost compression.
thats why poeple put 250 heads on 292s

KEITH'S75CUSTOM
8th-August-2007, 05:58 PM
also check the local cylinder head shops they will usually be able to get them real fast, and might give you some money off if you give tham the old integrated(if its not cracked)

Richardlss
8th-August-2007, 06:12 PM
k, im stupid when it comes to all these terms and stuff, the most ive done to cars is changing out the rear end, shocks, spark plugs, oil etc... nothing major like digging into the engine.. but im just lost, if i could find a head that would fit a 250 (rather keep the compression) and id like to keep it new, i can do the searching for a head, but how do i know it will match up with the intake? do all 250ci heads match all 250 intakes? id imagine they should... and do i have to find a special carb to fit on the intake? i wouldnt think so all the pics ive seen just have a square bottom on the carb, so as long as i get the correct sizes they should match right? ex. 4b carb with a 4b style intake manifold, and a 4b style intake with a 2b carb as long as i get a conversion kit... sorry for the hastle guys, i just wanna make sure i get it right:o

KEITH'S75CUSTOM
8th-August-2007, 06:30 PM
most 4 bbls will fit a four bbl but some require a adapter plate( pretty cheap)
i will look and try to find somwhere on the web that sell new heads and yes any gm 250 head will work with the offy intake. so will any 194, 230 head

Twisted6
8th-August-2007, 07:51 PM
Ok a quick compression lesson lol. The 194 head is the Only head that will change compression. a 230, 250, 292. Pretty much all have the same CCs in the head VERY little difference in CC And again that also depends on the year the head is. a 194 head can have either CC chamber 60.32 cc - 72.80 cc. The 230-292 heads 72.38, 72.76, 72.80, 74.00, With a Odd ball one @ 75.5 CCs and the 75.5 CCs was from a 230 ( head casting # 3872708)
292s had either a 72.38- 74.00 CC

Hope that helps.

ALL intakes will inner change from 194-292. and I'll keep a eye out on a intake for you as well.And just about any parts house
or mail order companys carry the 2-4 adaptors.

Paul Wright
8th-August-2007, 10:39 PM
Keep in mind that compression is power. If you can bump up the compression at the same time as getting some flow, you'll gain some extra power so it will be a double plus.
Figure out your CR but my guess is what you want is a small chamber 194 head. Along with the 2 barrel, Offy intake and a Header, some minor porting and a good valve job will really wake up your six.

Richardlss
9th-August-2007, 01:59 AM
ok i guess what will help me out most is finding a vehicle that had a 250, 230, 292 in it... seems like all the sites im searching through doesnt go by just the engine size, they want to let you search by make and model (seems stupid since most restoration cars never get the factory items back in it) so i cant look up cylinder heads for a 78 nova, cause they were integrated :( but if i knew of a vehicle that had a 250 with a non-integrated head, then i could just look for that vehicle, and find the head that i need...

summitracing has a good way of sorting things, but it seems like the more i narrow it down the more confusing it gets... maybe its just me, but everywhere i look i just find cylinder head fasteners:mad: thank you


maybe i just talked before i wrote... but a 74 came with a inline without an integrated head? if so i feel stupid:awkward:

Richardlss
9th-August-2007, 02:32 AM
oh and on
http://www.jcwhitney.com/autoparts/ItemBrowse/c-10114/s-10101/p-100000212884/mediaCode-ZX/appId-10681905/Pr-p_CATENTRY_ID:10000021288410681905

what does this mean below? its in the item description:

Note: Not legal for sale or use in California on 1966 and later registered motor vehicles. This product is intended for off-road or racing use only and is not intended or applicable for highway use.

i could use this for daily driving right?

KEITH'S75CUSTOM
9th-August-2007, 03:00 AM
This product is intended for off-road or racing use only and is not intended or applicable for highway use.

i could use this for daily driving right?

all that means is that it dosnt have all the smog equipment on it( which is a good thing performance wise)

KEITH'S75CUSTOM
9th-August-2007, 03:02 AM
look under 65 to 74 nova for it.

Richardlss
9th-August-2007, 09:54 AM
well i have the information i need, but now i just need to know where to find what i need, heres a few i tried:
www.jcwhitney.com
www.summitracing.com
www.yearone.com
http://www.exeterautosupply.com/Docs/Offenhauser%20catalog.pdf
http://www.nnnova.com/
www.classicindustries.com
www.autozone.com
www.edelbrock.com/
www.holley.com/

i looked through the years 65-74 for a cylinder head, but it seems most of them dont have them... anymore suggestions on sites i can try? its weird you can find more edelbrock parts on the other sites than you can find on the actual edelbrock website:confused:

KEITH'S75CUSTOM
9th-August-2007, 10:11 AM
for the head it would probably be best to try and find a local cylinder head or engine rebuilder and have them get you one

Paul Wright
9th-August-2007, 10:50 AM
You won't be able to find a new head. They stopped making them last century! You'll have to find a good used head and rebuild it.

Try Ebay or do what we used to do. Go to the old car boneyards and look under hoods. Sunbelt boneyards are more likely to have older inline sixes. Up here in Michigan all the good stuff rusted away.

Being informed will save you some grief. You'll need to know casting numbers and what to look under.
I would recommend buying a book on hot rodding Chevy sixes.
I saw one at Borders or try Amazon.

sgtsteve
9th-August-2007, 11:00 AM
Exactly what I said earlier!! Find a used head, or complete engine and throw that sucker on there. If you would rather not rebuild a cylinder head, I found this place on Ebay probably not a bad deal.

http://cgi.ebay.com/ebaymotors/CHEVY-250-292-CYLINDER-HEAD_W0QQcmdZViewItemQQcategoryZ33617QQihZ008QQite mZ180144787489QQrdZ1QQsspagenameZWDVW

Richardlss
9th-August-2007, 01:49 PM
You won't be able to find a new head. They stopped making them last century! You'll have to find a good used head and rebuild it.

Haha, explains why i cant find them :D well i wont need to buy it for a while, ill just cross that bridge when i get there

right now imma work on my shifter problems, then the intakes... then rear end, i cant remember what rear end i have ( i havent looked at my car in a long time now, been buisy working and getting a house) but since u guys know my situation with the head i want, intake, and i decided on a 4b carb instead of 2... do u guys have any suggestions on a rear end? or somewhat of a quick lesson on a back end? such as the difference in performance with bigger or smaller rear ends?

KEITH'S75CUSTOM
9th-August-2007, 02:39 PM
you need to find a 8.5 rearend, and id suggest 3.08 gears if its a street car.

but with an 8.5 you need a shoter drivshaft.

but i doubt that the inline will ever break the 7.5 you have now