ok, i'm trying to figure out how and what i want to build so i can research parts. i want to just do a 4" stroke and a 3.8" bore on my 5.3l. but i have been thinking about the 402 option.

a couple thing hold me back and thats having to buy more parts that would work fine for a stroked 5.3l. like my cam, its a 215/218 6**/6** 113+1 i think. its been a long time since i looked at the cam card. this will be twin turbo'd. will this cam be ok in theis motor or is going to just plan suck? also my worked over ls6 heads, will they flow well enough for a 402?

 

For a 402 you know you are going to need to use a 6L block, not the 5.3 block you have, right?

That cam will work fine and be very driveable.

 

The larger bore gives you so many more options down the road. Whatever you do, I'd start with a 6.0l block

 

 

yes i know i will need a 6.0 block. see that another thing i need to buy. lol

if my cam and heads will work then i wouldn't worry so much. but is it going to fall on its face at 5500 rpm or will it pull to say 6200 or so. i don't need a extreme high rever but i'd like to be able to pull at least to where the stock nnbs manifold like to pull to. one of those "whole package works together" things.

it like to pull good now but it seems the intake is more of the limit on rpm for me. three different cams and they all stop pulling around 6000-6200 rpm. i know some guys pull higher with stock mani but most don't weigh 6000lbs either.

 

to be clear, me asking if the heads will work, i mean will they flow enough. but i kinda already know they will. just need some reassurance i reckon.

 

Mike, are you running stock valves? Seems to me that I would want a larger valve if I were going to a larger cube.

 

stock ls6 valve. well they are actually 317 valves that i put in the bear ls6 heads. the heads flow very well. and like i said this will get twins this time. with a nnbs intake.

wifey wants a new 4 door wrangler for DD and off road play so the tahoe will not be driven as much. its getting push button 4wd/80e and 14 bolt rear. i'm tired of breaking awd xfer cases. the 149 is shot. can't go over half throttle with out it popping.

 

I run stage 3 TEA 317s on my turbo 408 -- they work great. yeah, switching to some monster heads would flow more, but that's what the turbos are for

It really depends on how "worked" they are. Don't get me wrong, stock ls6/317s will work, but they leave a lot on the table.

 

trying to remember but i think they were in the 320-330 range. a friend of mine had them and did a ton of research and ported one just to see how he could do by hand. then had them tested. turns out he did a real good job. but he only did one and gave them to me. so i had a local guy match the unported one and traded him my stockers for the work. they didn't have valves but i had a set of stock 317's and used those valves. so for the price of nothing i got p&p'd heads that flow real nice. hell i could tell soon as i put them on that even my part throttle power was up. like in hill climbing or pulling a trailer.