What direction to take? 402, 408, ect...?
 

I've hit a point in my time with my Trans Am where I want to do a build. Heads and cam won't cut it. I don't want to deal with the headache of boost at this point. I'm thinking stroker. I don't know what direction to head. I want over 500 at the wheels. This wouldn't be a racecar per say. More of an aggressive street car. I was debating a 402 as my buddy had one in his z06 and it did 525/515 at the wheels. (TSP shortblock, trick flow heads, patg cam, fast 90, 1 7/8 lt's, blah blah). This may be a washed up topic, but I really don't know where to go.

My question is, where to go? What size motor? Who's short block? Heads? Any input would be appreciated.

If i had a larger budget id go with the LS7 hands down

I've thought about it, but I feel like there are better bangs for the buck out there.

On a side note, if this is the wrong section for this thread, mods feel free to move it.

The bigger your bore the better your head options..

Not sure if this will help but.I have a 404 Ls2 Stroker.

Just finished Dyno last week. 499 RWHP and 486 Torq.
LS2 404 Stroker
-10 cc Malhe pistons
Callie crank and rods
Fast 102
1 7/8 long tube custom
Ls6 Stg 3 heads
239/247 113+1 650 lift
dual springs and harden rods
M6.
25% UDP

Better heads would def add probly 15-30 rwhp over the LS6.

That helps. Ls6 heads due to budget or personal choice?

I bought before I knew I was gonna stroke the motor.
Just left them on since I had them. Would have changed the heads but reached 500 rwhp and that was my goal so never changed since I reached my goal.

I don't mean to thread jack here, but i just wanted to know what mpg you get at 500whp? Thats how much i would like to make and still have the car as a DD. I have a stock LQ9 block im getting ready to do. Do you guys think i can get 500whp out of a 6L? again sorry about the thread jack..

Easily if done right. There are ls1 cars making 500rwgp on stock cubes.

Search Patrick G and he has two very in depth threads about making 500whp on stock cubes for both 5.7 and 6.0.

Also note the cathedrals are a better choice for smaller bore motors...not to say a square port cant do the same, but do your research and decide for yourself.

Iron block 408 is going to be cheaper than the rest but add 110lbs over the nose of the car.

With that said, the price of an LS2 and LS3 block are similar, so I'd go LS3 all day long to get the added bore. LS7s are in another price realm. So I think LS3s represent the best of everything (bore, block weight, price). It's all about trade-offs. I'd stick with a 4" stroke because none of the LS series blocks are really optimal for 4.125" stroke - tradeoffs there as well with the piston rocking at the bottom of the bore, needing shallow ringlands, etc. 4" and a 4.07" finished bore gives you 416cid to work with, which is enough for good power.

The LS3 bore works well with just about any head not named LS7. I'd probably stick with a Cathedral Port option like the TFS 245s and run a custom cam designed for how you drive the car. 500rwhp won't be a problem as long as you have a FAST 102 and 1-7/8" headers. Depending on the cam and attention to detail in the build, 550 is attainable as well. I say the 245 because Tooley and TEA will probably recommend that over the 235 with the added bore size. Talk to Mamo as well about the AFR 230 and 245 options.

TSP also has a 250cc aftermarket LS3 option which looks promising and isn't really any larger than the 235/245 cathedral port offerings from AFR or TFS.

I'd go with the lightest valves you can find in any of those heads and build a very stable valvetrain with good springs, stout pushrods, and good lifters. And depending on the custom cam you select (especially if you use endurance type lobes from say EPS), you can have a solid powerplant that puts out great power and that will last 40-50k miles on a set of springs without much trouble.

A larger motor will drive much better than a 5.7L and make a lot more torque. But a 6L or 6.2L can easily make 500rwhp with the right heads and another 20-30ft-lbs of torque over the 5.7L.

That was what I was looking for. Thanks.

Recently, we had sold a customer a 408 that made 546rwhp, 526rwtq

Quick rundown
Fast ported intake
Fast TB
ETP 245s (he found an old set and we refreshed them)
Roller Rockers
11.2:1 compression
Scat ultralight rotating assembly
Wiseco custom pistons
Custom Grind Camshaft

Any questions, please give us a call!
(916) 757-2326
-Kyle