1SLwLS1

iTrader: (6)

which would you belieive yield the most on the stock short block with an MS4 and some PRC 215s, Fast 92/95?

I know they are very close in power, but some people are pro stepped and other not.

Looking for technical theories why one may be better than the other

transAm-98

iTrader: (1)

To be honest, both of those seem a little big for your setup. 1 3/4 should be fine or 1 3/4 stepped to 7/8 if you want to drop the cash

1SLwLS1

iTrader: (6)

You think so? I would figure no restriction would be best. Little back pressure as possible

GeorgeR@kooks

1SLWLS1 first thanks for choosing our product to run on your build. For your combination we would recommend that you install a set of our 6505s witch is our 1 3/4x 3 headers if you plan on going slightly bigger in cubic inches then I would say 6505-1s that is our 1 3/4 x 1 7/8 x 3 stepped headers. As for the x pipe you could go with our 6502s for our 3" off road or our 6502ms for 3" catted version. If you have any questions feel free to call us toll free at 1 866 586 KOOK.Thanks George R

twitchtwice

iTrader: (12)

typically people get bigger then 1 3/4 when they go up in cubes

transAm-98

iTrader: (1)

My 408 is still running some old QTP 1 3/4's. I'm sure I'll go bigger eventually but i'm just saying if my 408 is running as strong as it is on 1 3/4's, a 346 should be fine with them.

1SLwLS1

iTrader: (6)

gotcha. Are the exhaust ports on these heads aroun 1 3/4? I reckon I will probably just run 1 3/4 or maybe 1 7/8 incase I decide to up the cubes down the road.

AznMuscle

iTrader: (7)

If anything, I agree with the 1 7/8th for later on. That was my original plan as well....but can't pass up a $500 complete exhaust system: 1 3/4 LTs, ORY, and LM catback lol.

Kooks: You guys make x pipes for F bodies? Or is that for vette only?

2000_SS

iTrader: (24)

i've got 2" on my 454....thay're HUGE...1 3/4" or MAYBE 1 3/4 x 1 7/8 x 3 is fine for your build.

SSIRBY

iTrader: (44)

i had a 346 with 1 3/4 kooks. now i have 408 with 1 7/8 stepped 2". very nice headers. when you go 383 or bigger, sell the 1 3/4 and go with 1 7/8.

allngn_c5

iTrader: (3)

My 1 3/4 lg pros work great on my 402, but there is obviously more power to be had by jumping up to the 1 7/8. Stay tuned for my results when the switch is done. (It'll be a few months)

SiL3NtXWS6

iTrader: (17)

I had 1 7/8 - 2 inch on my 408. They were even plenty for that. 55whp with the headers and fast 90/90 over LS6 mani and pacesetter headers.

I would do 1 3/4 and at most 1 3/4 stepped to 7/8.

BAD ASS TA WS6

iTrader: (5)

I made big power with my bolt ons and Kooks 1 3/4" LTs and a 230 cam.

I wouldn't hesitate to buy them again.

If you were heads/cam with a 90+mm intake setup, the step to the 1 7/8" might be worth it. But the 1 3/4" LTs have been proven for years.

bottelfed377

I remember reading about a stock cube N/A car making a little more power going from 1 3/4 to 1 7/8, but i cant find that thread.