Js04sILVerBullet

I bought some LT headers awhile back for cheap for my 88GT that are 1 5/8, but my question is should I ditch those for some 1 3/4 LT headers? or would those be overkill for my setup which consist of

347 with
edelbrock performer RPM aluminum heads
trickflow 1.6 roller rockers
X-303 cam
BBK SSI upper/lower intake manifold
BBK 70mm TB
C&L 76MM mass air meter
4.10 rear gears.

thanks for any input

also would 3in. exhaust be overkill as well?

mjr46

I run 1 5/8's with my 347 and 2 1/2 exhaust with excellent results

SteveSkal

You've got a pretty big set-up, you may benefit from the larger headers, with a sacrifice of some low end power but with those 4.10's you got that shouldn't be an issue, oh yeah and one other thing, you should probably go with a 75mm throttle body, that 70 is prob too smally for your set-up.

primetime5.0

the tb is fine

Js04sILVerBullet

Alright thanks

94StinkinLincoln

the bigger the better.

the 1 3/4's can be hard to get fitted right, but worth the hassle.

OnyxCobra

That's definitely not always true.


I think the 1 5/8" headers and 2.5" exhaust will be enough.

94StinkinLincoln

a 347 needs to breath in and out, ALOT more so than a 302. now being he has the rpm heads, he wont make as much power as some other head combos.

i switched to the LT's for a reason, i was fighting mine earlier, they hit in different places on different cars.

im going to 3in all the way back for a reason, i have a BRAND NEW magnaflow magnapack 2.5 catback sitting on the floor, but i have decided to get 3in mufflers to go along w/ the midpipe i have...

83gtragtop

Hardly always true, though you will probably see more peak hp and tq with 1 3/4" with your setup but I don't think it would be a worthy upgrade.

83gtragtop

Usually you don't want 3" exhaust unless your making over 500hp.