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Discussion Starter #1
im considering doing a bbc and it will have a custom ground cam. it will be hyd. my question is roller or flat tap? its a big price tag for the roller cam and the flat tap is very cheap. the car is 98% street drivin and 2% drag. let me know what everyone things and why.
 

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what block? is it fixtured for a factory roller cam? what CI? what compression? gearing?...what intake? head size? valve size runner size? carb size?

you have heard it many times, combination, combination, combination.. well.. you goals and car performance is paramount.....

if its a Mild app.. I think your referencing a 540 if its a mild build.. why go 540.. a 454 will put ya in the ditch just as fast as the 540... save a few bucks... IMO making 550hp with a 540 is a diminutive when 550hp can be had with a 454 very easy and very streetable....

now 700hp 540 and 700hp 454.. vast difference in cost....

If you just going to be a cruiser.... build a stock block 454 and put the cash else where....

If However you funds are unlimited.. then ignore me...
 

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Discussion Starter #3
I have a 454 2 bolt block. i wanna put the 4 bolt aftermarket caps and an eagle rotating assy stroked to a 489 or 496 depending on what it needs bored. and while im at it internaly balance it. than run about 10.2:1 compression with brodix race right oval port heads. and a rpm air gap manifold with 750 carb. the gears are 3.42 with a m 21 4 speed. its in a 69 nova. i want it to have a powerband of idle to 5500. thats all i ever really take it now. i dont need a rough idle i just want a lot of torque. i dont race it very much so streetablility is key.
 

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you can save some more money.. you dont need 4 bolt caps.. bbc have large registers... there are thousands of 2 bolt BBC turning in excess of 8k RPM on a studded 2 bolt block...

a 5500RPM does not need a large head... and a 310 or small cc runner will be just spiffy on a 496...

consider a 268 cam. right now, Lunati is the king in cams whit its latest offering in the VooDoo line up...

Fi it were my street build I would opt for the 274 tho....

with the 750 carb it will be very snappy and the Air Gap intake you'll make thunderous Bottom end (like you need more with a 496:devil:)
 

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Yeah just stud it.... if your max RPM is below 6k.. studs would just be added insurance.....

I have known many 2 bolt blocks that lived in the 7.5k rpm range and lived many a happy year...with just the addition of arp bolts, not studs:D...

the 496 option is a good choice.... just pick as light a rod and piston and you can... it will be a internal balance anyhow..... if budget allows, Ti. retainers are a good thought for a BBC....

for Insurance... mag the block and sonic check it.. before any work.. that will tell ya whether a +.060 is ok and if there are any trouble spots...
 

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Discussion Starter #7
Ya i am going to do all the machine work possible on this thing. take my time. but im pretty sure im also going to put beehive valvesprings on it too. go expensive on valvetrain and save myself problems. do you think i should do roller or flat tapped cam?
 

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The weak link in the BBC is not the main caps, the 2 bolt caps are just fine. The issue is the bolts. A 2 bolt block for pump gas and ARP main cap studs will fix any issues! Same for a SBC.
THE BOLT IS THE WEAK LINK!


Cam, you can go flat tappet and be SO SO.

or you can make the best of your engine with better performance with a roller. The roller profiles are not just a little different. the end result is better HP, Torque threw the entire power band. And making the power band itself wider. With todays oil issues and flat tappet failures on the rise. Roller would be my only option.

Based on the same setup.
A roller 454 will kick a 496 flat tappets "A" IMO!

Herbert has good prices on roller setups.

AL
 

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Since your dealing with a MK4 block.. a retrofit Hd roller is way off the chart in cost... a Hyd FT cam is a great choice provided you take the precautions and run the RIGHT oils..... have the lifer bores checked out for sure for proper lifter to bore size...

If you were using a MK6 or MK5 block then the HYD Roller is a cake walk and cost effective....
 

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I have a 454 2 bolt block. i wanna put the 4 bolt aftermarket caps and an eagle rotating assy stroked to a 489 or 496 depending on what it needs bored. and while im at it internaly balance it. than run about 10.2:1 compression with brodix race right oval port heads. and a rpm air gap manifold with 750 carb. the gears are 3.42 with a m 21 4 speed. its in a 69 nova. i want it to have a powerband of idle to 5500. thats all i ever really take it now. i dont need a rough idle i just want a lot of torque. i dont race it very much so streetablility is key.
Torque rules! thats all mine makes from idle to 5000 then its dead! Id do the 496 and get a 850 Q-jet from edelbrock, that will give you good mpg, great drivability, neck snapping throttle response and huge power, as for the 2 bolt block, you can add allen bolts to your caps, check a good machine shop to do this. A flat hydralic cam is really all you need if your not going above 5500, my 454 has a crane 272h cam (216/.515/110) and pulls the 3.31 gears nice, i think a grind in the 220's would work good on the bigger cubes.
 

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Discussion Starter #11
i think im going to go with a roller. if im doing it i should at least to me do it right. no problem with normal flat tapped cams but thats something i felt i would regret. i believe i am going to stick with the 2 bolt and put the arp studs in. get a good oil pump and an eagle rotating assy. what do you guys think of the brodix race right oval ports? i figured that since im not really racing it ovals would be better with the 270 cc intake runners.
 

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as far as port configuration goes.. you have to shift your brain to think how air moves.. and since this air is not being pushed but pulled by a vacuum you have to shift your thinking once again.... as how air will drag on the edges and have a very strong signal or vortex in the path of least resistance.

as for the port configuration.... a oval will flow better in terms of over all efficiency than a rectangle.. this is mostly due to stationary boundary layer air over a given surface and port configuration.

far and away right now the Ovals are showing over all better draw on air movement... but limited by volume... make sense?:eek:
 

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In all these head scenarios.

I have always come to one simple fact.

The bigger the head has never killer HP in any engine I have.

A engine is a air pump, more it can pump the more HP & torque.

I don't understand the concept of building a BIG cu engine only to choke it down with small heads.:eek:

The baddest BBC in 1970 454 LS6 450bhp at 5600 rpm
And the biggest difference between it and it's little brother was the heads.

And the factory rating was low! very low! More like 500plus HP

IMO
Al
 

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Discussion Starter #15
alright, i dont know too much about big blocks so im going to see what you guys think i should get. you guys have a lot more knowledge than me so let me know what you think i should make this 489/496 stroker. compression, heads, and cam, i am dead stuck on a rpm air gap and a 750 carb. at least for now. but let me know what you guys think. thanks!
 

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my advice do a search for what you're doing. There were lots of threads on this subject. Maybe instead of going hyd roller try a nice tight lash flat tappet solid lifter cam? makes the power you need and saves some money and contrary to popular belief you don't have to adjust them as often as you think. They do require periodic maintainence.
 

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alright, i dont know too much about big blocks so im going to see what you guys think i should get. you guys have a lot more knowledge than me so let me know what you think i should make this 489/496 stroker. compression, heads, and cam, i am dead stuck on a rpm air gap and a 750 carb. at least for now. but let me know what you guys think. thanks!
Why are you stuck on the 750 CFM carb? You may want to consider an 850. A 496 will move a lot of air.
 
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