Cam choice- LT1 or summit 8800?

International47 · Jul 5, 2024

Motor is back from machine shop.
looking for advice on what cam to use.

tbi 350 roller block .40 over with summit flat top pistons
average in the hole measurement is .022, so a .015 head gasket should be good for quench.
guessing 9.3:1 ratio.
heavily ported tbi heads and ported Edelbrock 3704 intake.- heads and intake should flow close to stock vortecs CFM.

I'm looking for usable low down to mid rpm torque.
Its going into a old hot rod truck, max weight 3000lbs, using the 1995 4L60E trans and EBL computer, 3.42 gears.
truck is just for cruiseing around, no need for high reving racing.

I have a 1995 LT1 copy cam- melling 1336. 201/208 447/459 LSA117

locally I can get a new summit 8800 cam. 204/214 450/450 LSA 112

Thoughts or opinions on either cam?
Thanks

SNCTMPL · Jul 5, 2024

You have ported the heads and intake, are you running a stock tbi or a bored one?

I think lsa on the Melling is a little wide, and I’m a fan of the Summit cams. With the specs you have given I would go with that Summit cam, and if you’re using a 46mm throttle body probably the 8801.

International47 · Jul 6, 2024

SNCTMPL said:
You have ported the heads and intake, are you running a stock tbi or a bored one?

I think lsa on the Melling is a little wide, and I’m a fan of the Summit cams. With the specs you have given I would go with that Summit cam, and if you’re using a 46mm throttle body probably the 8801.

the opening to the intake is 50mm, but its a stock tbi with the usual mods ( lip ground off, shaved bar, pod riser, tbi spacer that is open center and tapered to the 50mm intake opening)

heads and intake should flow a bit above 200cfm each port, I've read the stock tbi is capable of 450+ cfm?

sntrym · Jul 6, 2024

I'm running a Comp XR258 206/212 480/487 LSA110 on a crate 350 bottom and 46mm TB. Gobs of torque at the low end and good high end (up to about 5200rpm) if you ever need it. If you're down to those two choices, I would go with the Summit cam.

Erik the Awful · Jul 6, 2024

Get accurate numbers for your engine, and then call your favorite cam company. Don't trust us weirdos with your engine.

Block stock or decked? How much?
Piston depth at TDC?
Piston cc +/-?
Combustion chamber cc?

I can run the numbers and tell you what your actual static compression ratio and quench will be, and I can even calculate your dynamic compression ratio if there's enough cam data available.

Komet · Jul 6, 2024

LT1 cam will probably do you just fine, Summit cam likely picks up a bit of power on the top end.

Supercharged111 · Jul 6, 2024

Komet said:
LT1 cam will probably do you just fine, Summit cam likely picks up a bit of power on the top end.

Why do you say that? The LSA would imply otherwise. I've been pretty impressed by the low end on my LT1 as it gets dyno'd annually, but that narrow LSA (and associated earlier valve events) should give OP what he's after.

PlayingWithTBI · Jul 6, 2024

International47 said:
using the 1995 4L60E trans and EBL computer,

What are you using to control your Trans? The EBL won't.

Komet · Jul 6, 2024

Supercharged111 said:
Why do you say that? The LSA would imply otherwise. I've been pretty impressed by the low end on my LT1 as it gets dyno'd annually, but that narrow LSA (and associated earlier valve events) should give OP what he's after.

Well I'm not an expert but I was under the impression a wide LSA is good for low end power because less overlap builds cylinder pressure quicker, and the lesser reversion leads to a smoother idle (and easier to control emissions). The shorter duration of the Melling also contributes to favoring the low end.

The Summit cam has slightly more duration (favors top end) and the 112 LSA should make more power because it's closer to 108, and (if I didn't regret this post yet, I surely will now as I'm not a DV fan) David Vizard says you can choose other LSAs for a SBC but you would be wrong if it's not 108.

So, if you poorly crunge that together, in my mind they're mostly the same except the Summit cam is going to let a bit more air in which will probably tilt the curve up at the top (5500rpm) but lose a few numbers at the bottom.

Supercharged111 · Jul 6, 2024

Komet said:
Well I'm not an expert but I was under the impression a wide LSA is good for low end power because less overlap builds cylinder pressure quicker, and the lesser reversion leads to a smoother idle (and easier to control emissions). The shorter duration of the Melling also contributes to favoring the low end.

The Summit cam has slightly more duration (favors top end) and the 112 LSA should make more power because it's closer to 108, and (if I didn't regret this post yet, I surely will now as I'm not a DV fan) David Vizard says you can choose other LSAs for a SBC but you would be wrong if it's not 108.

So, if you poorly crunge that together, in my mind they're mostly the same except the Summit cam is going to let a bit more air in which will probably tilt the curve up at the top (5500rpm) but lose a few numbers at the bottom.

Less overlap builds less cylinder pressure, this is part of the equation for OEMs ditching EGRs. Less cylinder pressure = less torque. Wide LSA will have a wider power band with a lower torque peak all else being equal.

Cam choice- LT1 or summit 8800?

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