velox65

iTrader: (9)

Just bought a 91 bird, I plan on putting a 6.0 ls in in with a msd box and carb intake. Now I'm shooting for 500-550whp but numbers are just that, numbers.But it's nice to have a goal.
In terms of heads if I keep stock CID would l-92 be ok or Cnc 243s?
Stock cubes is it reasonable to get there, if I do have to stroke it what heads then? Either way I plan on new rods and .030 pistons.

Car will be a "street" strip car and a automatic.

Sales4@Texas-Speed

iTrader: (4)

If its in the budget I would definitely look at stroking the motor. Without the extra stroke and cubic inch I think it would be tough to make the power you are looking for. I would look to the L92 heads if you are looking for more top end power, or the 243s if you are looking for a broader power band. The L92s have a large valve and intake runner that won't make as much low end power but will definitely move air to make power up top.

PREDATOR-Z

For that kinda power, plan on getting the best heads $$ can buy. Still those numbers will be tough in an auto on those cubes.
IMO if you keep stock cubes, go FI.

Blk98Vert

iTrader: (2)

I can see that kind of power with a proflo intake and a cam designed for it and that pulls to 7200ish. My friend made 470rwhp with a MS4/Proflo combo on stock 241 heads through a 6 speed. Obviously better heads will get you there but I can see it hapenning. The last 346 I remember breaking 500 was Carteks Trans Am, I believe they were 517rwhp through a 12 bolt, 6 speed, FAST 90/90 and their 4x cam and 4x 243s.

velox65

iTrader: (9)

Stroking isn't out of the question, just if I can make the power stock cubes and put the money in better heads and forged rods /pistons. I'll go that route and punch it .030

usmcpi

iTrader: (2)

The power can definitely be made on stock cubes. Quite a few LS1 346 engines have broken 500rwhp...such as this 522rwhp/445tq A4 car: https://ls1tech.com/forums/dynamomet...4-10-11-a.html

What's your budget?

velox65

iTrader: (9)

No real budget set in stone, not unlimited money, but I have time lol. I'm figuring on stock cubes , with good rods/pistons and the right heads about 4-5k less if I can find a good used deal. Then comes the trans and rear end...

velox65

iTrader: (9)

How does a set of 243 heads Cnc ported(prc,ai?) forged rods .030 pistons cam speced to match. 12:1 compression or so, good carb and intake, 1 7/8" headers sound. It seems like this would net me "close" to my goal. Or am I way off?

Fbodyjunkie06

iTrader: (10)

With the money it takes to make 500rwhp on a stock cube motor you can take that same amount of money get a forged rotating assembly with 4.030" pistons, 4" crank and stock L-92 heads and do the SAME thing, and obliterate the amount of torque that could be made on the stock cube motor.

No replacement for displacement

We have some pretty competitive pricing on our 402/408 packages if you're interested.

garygnu

maybe look at a stroker rotating from TSP ,and look at some ported l92 heads.you will need off set rockers and a intake for those heads.are you going to use the elderbrock intake ignition set up ?you will benefit with from a custom cam ,get the cam last.

velox65

iTrader: (9)

Im going to get the msd 6ls control box, and Im interested in any stroker kits, if the price is right. I was actually looking at a 396 stroker as I prefer a undersquare setup. That and no one really uses them.

Fbodyjunkie06

iTrader: (10)

I think a 4" stroke and 4.030" bore would be your best bet.

The 3.9 crank is going to be more expensive and would really not give you anything in regards to power over a 4" crank.

In fact it might actually lose some power unless you really stepped up the head selection, cam selection and were willing to turn it more rpm to make up for the VE you'd lose with the smaller stroke.

velox65

iTrader: (9)

I'll do a 402, set of cnc ported l92s, edelbrock intake (super victor?) if they have em for carbs and custom speced cam with the MSD 6ls controller probably electric water pump and underdrive pullies as well.

Sales@Tick

iTrader: (3)

Super Victors are a carb style intake out of the box. They use a 4150 or 4500 mounting flange, same as a 4150 or 4500 accufab/wilson style throttle body would use.

I would use the Super Vic in this application all day, it will provide more power due to the added plenum volume which a bigger motor will want and respond well to.

A custom Tick cam would really round out that package nicely