'72 Big Blocks?

gordonquixote

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Lifetime Gold Member
Jul 18, 2006
3,036
Tallahassee, FL
A 1972 LS3 had a nosedive in power compared to previous years due to .gov regulations. Do some homework before jumping on the 1st big block to come along.

Motor homes and tall decks fall into the 'pass' category as well.

A Tarantula will not accommodate a stock flat hood ( a Torker II is perfect with a drop base air cleaner). Power falls flat in the low 5,000 RPM range though.

+1 oval port heads
 

flowjoe

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Staff member
Lifetime Gold Member
Feb 7, 2006
8,146
SoCal
gordonquixote said:
A 1972 LS3 had a nosedive in power compared to previous years due to .gov regulations. Do some homework before jumping on the 1st big block to come along.

Motor homes and tall decks fall into the 'pass' category as well.

A Tarantula will not accommodate a stock flat hood ( a Torker II is perfect with a drop base air cleaner). Power falls flat in the low 5,000 RPM range though.

+1 oval port heads
The '72 LS3 is the same engine as the '71 LS3. It's just that GM started giving HP figures in net rather than gross (300HP in '71 vs. 240 in '72). Both years use the oval port heads with 2.06/1.72 valves and 113cc combustion chambers and the same hydraulic cam shaft with .398/.430 lift figures. Same compression ratio etc. The real fall off is from '70 to '71 where the L-34 was making 350HP (gross) using a much smaller combustion chamber (100cc) and a more aggressive cam shaft (.461/.480 lift).

But I think the OP is not looking to pick up a '72 LS3 nor recreate one exactly I think he already owns the car pictured above). If I understood correctly, I think he wants to create a '72 with a BBC of some sort that looks cosmetically like a '72 SS LS3 car.

Maybe I misunderstood him.
 

Thunderkyss

Veteran Member
Sep 16, 2012
223
Texas
flowjoe said:
But I think the OP is not looking to pick up a '72 LS3 nor recreate one exactly I think he already owns the car pictured above). If I understood correctly, I think he wants to create a '72 with a BBC of some sort that looks cosmetically like a '72 SS LS3 car.

Maybe I misunderstood him.

You're correct, my car doesn't have an engine. I'm contemplating putting a big block in this car & if I do, yes I'll want the visual cues that says big block.

I am, however, also interested in any information available about big block 2nd gens, so keep up this discussion, it's been really good & informative so far.
 

fnoblitt

Veteran Member
Jul 4, 2009
437
riverside calif.
hoodclearance002.jpg
i like mine
 

shad_van

Veteran Member
Jun 15, 2012
212
las vegas, NV
The camaro is a fairly light car all things considered. When you put a lot of torque behind them, they are hard to get hooked up. My 71 SS396 has this problem, also the body tends to flex a lot. mine is mostly stock, it has the orignal engine, but I am assuming the engine was rebuilt at some point with a bigger camshaft. I havent torn it down because im having to much fun driving it. Thats my project for this winter.

I would look at sub frame connectors and some of the traction / wheel hop bars that are availeble. also look at beefing up your drive train components, Drive shaft u-joints and a TH400 if you go with an Automatic or an M21/22 if you go with a stick. several aftermarket companies also offer beefed up version of the M22 and even a M22 with an over drive 4th gear. I have also seen T-5 5-speeds and T56 6speed swapped in. I dont know how well they can handle a big block.

I have built a lot of big blocks in my time, mainly for flat bottom speed boats and few street/strip cars. I have found the Th350 & TH700R4's dont last very long here in Las Vegas summers behind a big block. I dont know where you live, but you may also want to consider a trans cooler if you are running an Auto.
 
Last edited:

Thunderkyss

Veteran Member
Sep 16, 2012
223
Texas
shad_van said:
The camaro is a fairly light car all things considered. When you put a lot of torque behind them, they are hard to get hooked up. My 71 SS396 has this problem, also the body tends to flex a lot. mine is mostly stock, it has the orignal engine, but I am assuming the engine was rebuilt at some point with a bigger camshaft. I havent torn it down because im having to much fun driving it. Thats my project for this winter.

I would look at sub frame connectors and some of the traction / wheel hop bars that are availeble. also look at beefing up your drive train components, Drive shaft u-joints and a TH400 if you go with an Automatic or an M21/22 if you go with a stick. several aftermarket companies also offer beefed up version of the M22 and even a M22 with an over drive 4th gear. I have also seen T-5 5-speeds and T56 6speed swapped in. I dont know how well they can handle a big block.

I have built a lot of big blocks in my time, mainly for flat bottom speed boats and few street/strip cars. I have found the Th350 & TH700R4's dont last very long here in Las Vegas summers behind a big block. I dont know where you live, but you may also want to consider a trans cooler if you are running an Auto.

Thanks for the heads up. The car doesn't have a motor, but the guy I bought it from had a 454 in it. He'd have sold it to me for an extra grand, but I turned it down. I was thinking LSx at the time.

But the TH400 is still in there. I told him to take it as well, as I was thinking a T-56.

I'm a long way from putting a motor in this thing, but I'm thinking I'll keep my eyes open for a fuel injected 454 & 5 speed from a late '90s one ton.

He's got some traction bars on it, no sub-frame connectors & the passenger side frame rail has lost a huge chunk to rust....
 

shad_van

Veteran Member
Jun 15, 2012
212
las vegas, NV
Thunderkyss said:
Thanks for the heads up. The car doesn't have a motor, but the guy I bought it from had a 454 in it. He'd have sold it to me for an extra grand, but I turned it down. I was thinking LSx at the time.

But the TH400 is still in there. I told him to take it as well, as I was thinking a T-56.

I'm a long way from putting a motor in this thing, but I'm thinking I'll keep my eyes open for a fuel injected 454 & 5 speed from a late '90s one ton.

He's got some traction bars on it, no sub-frame connectors & the passenger side frame rail has lost a huge chunk to rust....


I would definately fix the frame rail before slipping a big block in it. also check the b-pillars where they meet the roof line. High performance second gens have a tendancy to crack at the lead solder joint if they are driven hard. new body bushings also help a lot in reducing flex.

Also back in the 70s-80s. herb adams VSE made a firewall brace that bolted to the firewall and the control arm mounts that also reduced flex. I have a very old car craft mag from the 70's that shows them. i will see if i can scan a pic latter tonight. i dont know how much prower or what you plan to do with the car after you put the big block in it. but if you drive it hard you might think about something similar.
 




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