72 engine modification

[bobfil]

I have base 350 (200 hp) with Eldebrock Performer Manifold and a 4 speed, and would like to put in cam and heads as the optional engine in 72 had 350 (255 hp) LT1. What cam and heads were they? Thanks for any info. Oh yeh does any one know of where you can get seat belts and retractors at reasonable price. Thanks Bob

 

[KANE]

I have base 350 (200 hp) with Eldebrock Performer Manifold and a 4 speed, and would like to put in cam and heads as the optional engine in 72 had 350 (255 hp) LT1. What cam and heads were they? Thanks for any info. Oh yeh does any one know of where you can get seat belts and retractors at reasonable price. Thanks Bob

From the looks of the seat belt portion of your post, cost is concern. Since you don't seem to care too much for originality and you are going with a late model intake and you are in the market for heads... you have lots of options. You may want to think about Vortec heads and a Vortec bolts pattern intake. You could get both out the door for under $1,000.

Next, you'll need a cam- that in of itself is another debate!

 

[pgtr]

To add to DarkSharks post - there's a lot of differences between your L48 and an LT1. The LT1 had a solid lifter cam for one.

Rather than go that route look at the L46 or L82 as possible guides since they produced good HP and retained hydraulic cams. As a starter I'd look at the L82 cam as a baseline but maybe look at something similar and more modern w/ a dual profile. (Crane cams et al...) As to which cam specifically - as Darkshark mentioned - that's a chapter until itself - I'm just offering a possible ballpark starting point. That and consider some flat top (w/ reliefs) hypereutectic pistons. To keep cost down that could be phase 1 and phase two might be to consider the heads (or work w/ the heads you already have). Oh and re-curve your distributor accordingly.

 

[6880 Mike]

3973487 or 3998916 for the heads; the 487s are probably already on your car. You will want the LT-1 camshaft and conversion to solid lifters. LT-1s also had transistor ignition, but a recurve on your existing tach drive unit will probably be okay. Carb is the Holley R6239A and you will want the aluminum LT-1 intake or equivalent. You will also need the additional height of the LT-1/BB hood.

Any good LT-1 reference should have a complete GM parts list.

 

[Crimson Thunder]

Most people would hate how their car would drive with a stock LT-1 cam.(no bottom end torque)I like the idea of stock Vortec heads with a spring upgrade and then call your favorite cam company and see what they recommend.

 

[pgtr]

I agree w/ sharkcar71 re the LT-1 cam. Maybe not 'hate' but without also adding gears - for toodling around on the street a 300 or 350 horse hydraulic cam is more pleasing IMHO. Further there is a LOT more to an LT1 than a cam change. Different ballancer, pistons, distr curve, larger valves (same head in some years?), threaded studs, forged crank, guide plates (?), 2.5" exhaust (strangely necked down at the manifold), ... and I'm sure other things I'm forgetting. The cam brings it's power at a MUCH higher rpm - higher than an L48 was originally intended for. The LT1 cam does sacrifice low end torque. I'd guess optional rear end gearing was popular with LT1s for obvious reasons.

I don't believe the LT1s came w TI in all years but I could be mistaken. In any event TI and the distributor curve don't really have anything to do w/ each other. Recurve the distributor as needed (I don't think the L48 for your year has an ideal curve) along with a modern electronic ignition conversion.

 

[Brooklinite]

...I don't believe the LT1s came w TI in all years but I could be mistaken...

'72's didn't have TI.

 

[Glen Braxton]

One issue I see with the Vortec swap, is the mounting of the ignition shielding around the dist. Many of the boy-racers like to discard the shielding, then they wonder why their radio sounds so terrible. (It' the lack of shielding, duh!). Anyway, the bolt angles of the vortec intake would require that the shielding brackets be bent and maybe drilled to fit the Vortec intake. Has anybody seen this done? I'd be interested in seeing the results as the Vortec has real performance advantages, but I also like the sound of my factory stereo.

 

[pat72]

Lt-1

'72's didn't have TI.

1972 did have a LT-1 option I have great site for you too see so send me your e-mail too pophee@cogeco.ca

 

[Brooklinite]

1972 did have a LT-1 option I have great site for you too see so send me your e-mail too pophee@cogeco.ca

I have a '72 LT-1 , however while it has a Transistorized Ignition today it didn't leave the factory that way. I'm certain of this because I asked a question about it's operation on the NCRS board a year or so ago and was basically attacked about how it shouldn't be there, etc, etc. (Never did get my question answered though.)

Shoot me an e-mail anytime at scott@72lt1.com