70454

I have a 70 LS5 Big Block. I am interested in swapping out my cast heads for aluminum heads offered by GM Performance. I was told the valves provide more lift and I would need to replace my cam. Is there anything else I need to replace? Also...I was also told that since I am strengthening the top of the engine, I risk damaging the bottom end? Is this true? And...sorry..one more question..Can I use my stock intake or should I upgrade to a LS6 aluminum intake? Thanks in advance..

Matt

MELVIN

If you go GM performance heads, you should not have to change out your cam.

The LS6 intake is made for rect port heads. Your LS5 should have oval port heads. It will all depend on what GM heads you are going to get, rect or oval port. Myself, I would stay with an oval port setup. These tend to be more streetable.

I would get a good intake to go along with those new heads you are compteplating. TOM454 has a LS5 that he has modded. Might want to ask him

MELVIN

If your bottom end is in good mechanical shape, dont worry about it...

zwede

The heads will make for a nice gain. You don't have to replace the cam, but a cam swap will get the most out of the new heads.

The LS5 bottom end is very strong and will have no problems. The LS5 runs a forged crank.

The LS5 intake will be a bottleneck. LS6 intake is rectungular port. You don't really want rect port heads, as you will loose low and mid range torque while only gaining power above 6k rpm, which is above your redline. Don't know what you can do for an intake. Torker II fits but is a bad intake. Personally I went with an L88 hood and EFI.

70454

Gents:

Thanks for the responses. I am planning on staying with the original oval port configuration. GM has some nice aluminum heads which are about $1800 complete for the pair. Any cam's recommended if I do plan to swap it out? The intake is my next question....any suggestions on an aluminum intake which would work? I am planning on keeping the big-block hood.

ScubaJKD

You might also want to take a look at the Edelbrock aluminum heads. They are reasonable prices, flow well, and will bolt right up. With any performance mod it is the sum of the parts that contribute to the whole perfromance equation. You will get a gain out of your new heads, but a matching camshaft will add to the equation. While you have the heads off I would consider doing the intake with an aluminum Performer RPM from Edelbrock. They are pretty hard to beat for the money and performance. You can take a look at the website and do an apples to apples comparison. Take care.
http://www.edelbrock.com/

SuperFast80

I am doing the same to a 72 LS5. Are you running headers? I am going to order either a Comp Cams 280H or 274XE.

ScubaJKD

SuperFast80, I am running the Comp Cams 280H roller cam in my 383 WOO HOO. :crazy:

SuperFast80

I take it that you like it. :D

70454

Superfast:

I am going to keep the same stock exhaust system with cast exhaust manifolds and 2.5" exhaust. I'll take a look at Comp Cams site. I bought CC 1.7 roller tips for my BB. More at the low end. Thanks.

Matt

71vettman

My 71 was an LS5 and when I rebuilt it I added some goodies. For the top end I went with the eddelbrock performer rpm aluminum heads, a comp cams "extreme energy" (hydrolic) cam and an LS6 aluminum intake. I want to eventually change to the performer rpm intake but I will need the L88 hood. I never drove the car before these changes so I cant compare but all I know is that there is plenty of low end power along with a great top end too.

Turbo-Jet

talk to Cam Potter. he as modded his factory LS5 intake and exhaust manifolds so that they work well with his combo. apperently the work isn't too hard at all for a pro to do. it is a nice option considering the limited choices of aftermaket intakes that fit with stock hood.

Steve439

You can get a pair of the GM heads for about $1600 at http://www.sallee-chevrolet.com
or http://www.sdpc2000.com

The Edelbrocks are pretty much the same but seem to run about
50 bucks or so more.

Tom454

I have a 68 Vette Q-Jet Aluminum Oval port with a Holley 6211 spreadbore currenlty installed on a LS5. Not necessarily a recommendation... just added info. The 68 manifold is a nice piece. Picked it up at a swap meet for $125.

MassVette

I believe Edelbrock makes the aluminum heads for GM--- they have different intake valve sizes, though; GM is 2.25", Edelbrock is 2.19"

Techno

I understand that there are several aftermarket heads on the market, some which offer a higher compression ratio for the street, they are built better for the lousy gas.
Something that wasn't mentioned is the care that is required with alluminum heads. As long as your willing to re-torq your heads I think a solid lifter would be a good option, if you weren't already thinking along those lines. I may be wrong but I think the alluminum is offering larger valves and better breathing along with the lighter wieght. If the valves are higher lift you may need to check your valve covers for clearance.
And although this is out of the price range, it would seem, I would also go with individual carbs(4 duels). If you need to change the intake why not?

LT1driver

Get a 68-69 tri power and the alum heads with a good comp cam and your car will rock even more. I had a 70 454 years ago and it rocked even then. :cool: :cheers:

marky mark

My 2 cents worth: Crane Cams Powermax H-272 with Edelbrock 100cc heads (oval port) and Corvette aluminum oval port, low-rise intake (68-69) port matched to your heads and a quadrajet tweaked by Lars. This will fit under your hood and would offer nice power and still be very streetable. Check your compression ratio as you should be shooting for around 10: to 1 with the alum heads. That will look good under your hood!This is my set-up on my '69 427 4 spd. except I don't have the Edelbrock heads....YET!!!
Regards, Mark :flag :chevy