0C_Williams@RPM

• Tale of two 416's •


Same Short blocks - different top ends and different headers - both installed in C5's.

Wish I had the same headers on both but it didn't work out that way - still, easy to see the differences.

One has cathedral heads (TFS) and Fast intake - the second is topped with our small bore LS7 heads & LS7 intake.

1999_TRC

So if I'm reading this right, you can spend $2500+ on the TFS/FAST setup, and get 30 less HP, and 6 more FT/lbs of torque

Good numbers for stock intake and heads.

WKMCD

Excellent comparison..can we assume approximately same range of cam? I know they will be different.

Nice work but then again, you know how I feel about rectangular port heads.

Kevin

dankhts

Good post, nice comparison, what's the difference in headers?

0C_Williams@RPM

kind of...the small bore LS7 heads with hollow stem intakes are $1895

additionally, the LS7 intake is half the price of a FAST.

0C_Williams@RPM

Kevin,

cams are identical -

Charlie

0C_Williams@RPM

The TFS package had a set of 1 7/8 kooks - the LS7 top end had a set of 1 3/4 "knock-offs) ...like to see this with a set of ARH 1 7/8"

C5Natie

So at 4500rpm the tfs make more power but then the LS7 heads take over from there? Those small bore LS7 heads are awesome.

1999_TRC

So what a minute, the story just get's better? The stock top end made those numbers, against the premium aftermarket parts, with 1 3/4" headers??

0C_Williams@RPM

neither package had any stock top end parts.

we built identical short blocks - compression, deck height, rotating mass, camshaft, etc..

customer one had a set of TFS heads ( with 1.8:1 roller rocker ams) and Kooks headers on his car. he opted to use those.

customer two - identical short block assembly - opted for small bore LS7 heads & LS7 intake - he had the 1 3/4 headers and opted to use them.

0C_Williams@RPM

pretty much

Jon B.

How much is the LS7 setup including the intake, and how much do you think I would give up on my 403" LS2? I'm running ported 799's right now with an LS6 intake.

0C_Williams@RPM

2550 including LS7 intake

But, on a 6.0 platform stay with the cathedral heads -

DANZGLASS

im still running these heads on my 402! been on for about a year now. just broke a 600+ whp gt500s heart last weekend! Thats with a shifting issue above 6200 that needs to be addressed.

0C_Williams@RPM

NICE !!

DANZGLASS

Yea the topend is just savage with these heads. Need more power though got used to it lol.

Jon B.

Wait, LS2 402? Mind sharing your setup? I'm planning on getting rid of my 799s and LS6 intake and custom cam. So, I'm open to ideas, I want to take advantage of the extra cubes as best as possible.

Thanks.

DANZGLASS

Yea no problem. Charlie used my car for the first round of testing on these bad boys!

http://ls1tech.com/forums/dynamomete...ore-c5z06.html

Jon B.

I wonder why he said I should stay with the Cathedrals? Thank you for sharing the setup though!

C5Natie

LS7 heads may be too much head for a smaller motor. You loose airflow velocity. Ive been in cars that have way to big heads for its setup and theyre dogs in lower rpms. Heads have to compliment the cam and cubes of the motor. One big package.