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originally posted by STOVEBOLT

4th Gen Big Block Conversion..

On my 77 I used the 520-2455-1 Hooker Competition's (for 70/72 BB Camaro) ceramic coated 2" primaries, fit great and I used the 305 motor mounts. 3rd gen BB mounts offset the motor to passenger side (not needed on 4th gen because they are front steer) and don't believe the Headers will clear the shock tower on passenger side if used.

You do have to grind a little off the corner of drivers side (clam part) of the motor mount (per instructions) easiest to fit on engine stand.

I also used the Hooker reducers, they are heavier gage and welded, rather than the thinner flanged slip joint junk.

Also used the Flo-Master Thunder Exhaust System for 67/68 Camaro (crossover, twin 40s, dumps down behind rear wheels) fit and sound great.

If you have a non/air car you will need to change the heater core to a BB core (Same as 67/68 BB Camaro) Original Parts Depot has them with the little trim plate. http://www.frontiernet.net/~irishhills/core.jpg

My car was non/air (smaller narrow radiator) so I cut out the right side of the core support to use the wider size air rad. and used a 4 core air rad., with the top hold down support from an air/car, also used a stock air/car shroud (with a little trimming on rad. side) I did have trouble with the stock GM clutch fan clipping the top of the shroud and found another stock clutch fan 1" smaller in diameter that corrected the problem.

Also if you use a TH-400 you will need to move the cross-member back to the next set of holes in the frame. (mine had the extra holes but I hear some don't) also using a TH-400 you will need a fine spline yoke, the one I found was 1" shorter than the yoke on my 305 car, but the TH-400 is 1" longer so it worked out perfect.

Other than that it's pretty straight forward bolt in.
 

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Non-AC car

Can someone confirm that for a similar planned SB to BB conversion in a 3rd gen, is the issue of whether or not the heater core/box has to be changed in a non/AC car because the non/AC radiator will not have the capacity to cool a BB? I'm hoping to avoid having to change my heater system as part of my conversion, and would rather deal with a radiator change, if that is the issue.

Thanks,

Mike
Tennessee
 

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Can someone confirm that for a similar planned SB to BB conversion in a 3rd gen, is the issue of whether or not the heater core/box has to be changed in a non/AC car because the non/AC radiator will not have the capacity to cool a BB? I'm hoping to avoid having to change my heater system as part of my conversion, and would rather deal with a radiator change, if that is the issue. (67/68 BB Camaro core will work)

Thanks,

Mike
Tennessee

It's a clearance problem with the core tubes/hoses clearing the head, with a BB core the tubes come out the other end of the core (closer to the passenger side) use the same heater box but with a BB core. (67/68 BB Camaro core will work)
http://www.frontiernet.net/~irishhills/core.jpg

Edit: Still have to change the radiator to a higher capacity (4 core or aluminum)

Also on a 3rd gen you will have to use BB motor mounts to offset the motor, so the headers will clear the steering box and use headers for a 1st gen camaro.
 

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'69 Nova - SB to BB - DONE!

I've read and discussed the various issues associated with the conversion that was completed on my car this week. I figured for what it was worth, I'd share a few details of my project. The shop could not get the BB frame mounts to work. They even tried switching them. In each instance, there was a conflict with the manual steering box. They then tried the original SB frame mounts. Everything cleared. Somewhere in the archives I read someone else solved the same problem in this manner. We did not change to a BB heater box. The hoses are very close to the passenger side head, but they clear. As for the distributor, we converted to an HEI, a regular, rather large distributor head. Again, it's a close fit, but it does fit, without distorting the firewall in any manner. We changed from a 350 ci to a 402 ci. I had new Hedmann ceramic headers, which fit very nicely without any conflict. I had all new 2.5" aluminized pipe with the 'H' pipe configuration installed while it was in the shop. I pick up the car on Monday and the shop owner has driven it a couple of times and said it's running great. I can't wait to drive it. I have done nothing to my stock SB radiator. The new motor has a clutch fan arrangement with no BB shroud yet and a short water pump. I'm anticipating cooling issues when the weather gets warm. I considered buying a BB shroud and continue with this mechanical fan. But, something tells me I probably should get a quality aluminum radiator and use electric fans, and do away with the mechanical fan. If anyone has a good cooling set that would work for me for sale, let me know. I believe this might be the way to go. Maybe this information will help some other newbie toying with a similar conversion...Mike, Nashville, TN area
 

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On our 69 - an original 6 cyl car - we used the original 6 cyl motor mounts for the 402, over the counter ( at the time) TH400 trans crossmember, and 'swap meet Camaro BB headers '.
manual brakes, manual steering - NO clearance issues.

We also ran a stock ( auto parts store replacement ) V8 radiator ( the standard width one, not the slightly wider 'a/C' version ) .

402 LS3/ TH40, 10" converter, 4:10 posi = very quick, no overheating issues ( although note this was NOT street driven other than up and down the street in fornt of dad's shop :) .

not sure why there'd be a n issue with the BB mounts, all they do is move the motor FORWARD ( over my 56 cyl mounts anyways ) and slightly tilted for clearance... in fact an early super stock 'trick' was to use the 6 cyl mounts to gain an ever-so-slight rearward movement of the motor for weight transfer, not sure if that minimal ammount made much difference, but when you;re talking thousandths of a sec to win or loose... who knows. ..

your mileage may vary, but worked for us.

~ AL

(couple pics of the 69 on my cardomain page, under 'Sailoral " )
 

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BB mounts move the engine to the pass side as well as the 400 TH crossmember,for some reason some guys have made it work not using BB mounts,but if power steering is invovled it is an issue.The size and brand of header also matter.My power steer 69 BB car has less room then my manual steering BB car.Both OE BB cars.

The front steer is much better in the 4th gens
 

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Hey, where can I buy 67/68 heaterbox for big block Camaro?
And what kind of hedders from Summit (part number) do I need for my 1975 custom?
The engine I use is a 396 Big Block

Kim
 

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I removed the 305 from my 77 Nova and bolted the engine mounts to a 454 and dropped it into place. I changed nothing, stock heater box, stock heater core. I have a 6-71 blower so I had to get brackets for the alternator and power steering pump so I am not sure if using the stock pump would be an issue, I used a power steering pump with a remote reservoir. I used a th400 so I had to move the cross member location, but that was very easy.
 

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BIG Block headers for 4th gen.

I am ready to purchase headers for my 75 custom,and was wondering if anybody used hooker super comp 2285.They are 2.125 primary tube full length headers. I looked up on their website and thats the part no # they list.They are also for 1st gen camaro,I have read that the 70 to 81 camaro headers would work.Any confirmation with a header that has that size primary tube would be appreciated.
 

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I used Hedman Hedders 65105, they fit ok. I had to clearance them a little with a BFH near the passenger side firewall, and also near the steering shaft. I don't know if I have the wrong motor mounts or what, but I also had clearance issues with the power steering pump. I had to cut the bracket for the pump and weld it back together. I do have solid body mounts though, so maybe you won't have these issues.

Good luck!
 

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Using stock exhaust manifolds

My 17 year old son and I are getting ready to do this conversion to his '77. It currently has a 250 in it. We have a '72 402 we're going to install.

From what I have read here, this swap looks pretty straightforward. We are rebuilding the engine stock, stock intake, Q-jet, etc., to keep the costs in check and I think a stock 402 should have plenty of power for a 17 year old kid.

The guy we bought the engine from has a bunch of engines, and a shed full of parts. He has exhaust manifolds as well. Do any of you know if we can run a set of stock exhaust manifolds, or will we need headers?

I'm looking forward to doing this, it should be a fun swap!

Mike
 

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My 17 year old son and I are getting ready to do this conversion to his '77. It currently has a 250 in it. We have a '72 402 we're going to install.

From what I have read here, this swap looks pretty straightforward. We are rebuilding the engine stock, stock intake, Q-jet, etc., to keep the costs in check and I think a stock 402 should have plenty of power for a 17 year old kid.

The guy we bought the engine from has a bunch of engines, and a shed full of parts. He has exhaust manifolds as well. Do any of you know if we can run a set of stock exhaust manifolds, or will we need headers?

I'm looking forward to doing this, it should be a fun swap!

Mike
the stock manifolds fit fine allthough i did have to modify my lakewood scatter shield so the pipe would not hit on one side
 

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bb 427 in gen 4

thought i would add a pic of a installed stock looking big block

i did end having to go with a smaller fan 17 inch i think and leave out the fan spacer
stock 396 ex mainifold
the truck power steering pump put the lines in the wrong spot went back to stock one for the sb nova and all was fine
 

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As these projects go, we just started the 402 BBC swap in my son's '77 Nova. It was an 250-6/TH350/non-AC car. What we've done so far:

We replaced the frame mounts with new stock mounts since the original ones were very mushy.

Converted from manual steering to power steering.

The engine came from a '72 Suburban. It had the engine brackets on it still. So we retained those to see if it would work. Well it does not. The brackets do not line up with the crossmember mounts.

I ordered a set of engine brackets from Summit Racing for a 4th Gen SBC. They arrived today. They look different from the truck brackets but not as drastically as I expected for some reason. So I hope they work.

This thread on doing this conversion jumps around a bit and some 3rd Gen people chimed in. I wanted to make sure we are clear that this engine should bolt in using the 350 engine brackets.

Thanks,
Mike
 

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Radiator bracket

I just did a BBC swap into my 75 nova and am using a prime cooling 4 core radiator. Obviously the stock shroud for the old rad does not work. Any suggestions on one that I can buy that will hold the rad in place. I read that you can use one from a car that had air cond but I can't seam to find the right one. So if anyone has a year/make/model of one from a car that will work, I would appreciate that. otherwise i will have to build custom brackets..
 
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