Hey guys. I'm doing a 402 LS-2 build with AFR 225 heads, fast 90/90 setup. Cam specs are 238/240, .605/.608, 113 lsa. Any idea what kind of HP I will make with this and should I have gone with a bigger cam ? I'm hoping for around 510+ at the wheels.
Thanks
Ron

 

ttt...

 

Cam specs are kinda small, what exhaust system?

I'll guess 510.

 

Exhaust is Mac mid length headers, through cats, and a slowmaster mufler... sounds good though.

 

Im thinking the exahust is going to be a major choke point. Macs are good and all but they are still inferior to long tubes on a stock engine, let alone a 402 LS2. Not to mention its still going through cats, and a flowmaster. All I can guess is <500 with your current exhaust and >500 if you upgrade to some true duels or something.

 

With that cam and exhaust I would be happy with 460RWHP in a 6 speed car. People make so much power on the internet but none of their cars go anywhere at the track. That cam is WAY to small to take use of that intake runner and the amount of air that a 402 cubic inch engine can exchange. But it all depends what your goals are with the car. That exhaust will rob you of an easy 25RWHP.

 

Cam shold definitely be bigger in my opinion. I would also get rid of the Macs and get a set of longtubes. If you want to save money go with something like Pacesetter longtubes.

 

You're buying a big $$$ huge flow 90/90 and a big $$$ huge flow AFR 225 on a big $$$ big power 402...

AND THEN YOU CHOKE IT OFF WITH MID-LENGTH HEADERS, CATS, AND SLOWMASTERS? ARE YOU NUTS?

 

PLEASE get rid of that exhaust setup, it's really bad. Go with long tube headers, and go either true dual, or throw out the cats and go with a nice catback.

 

Definitely dump the exhaust system for a 402 setup. I'm running QTP 1-7/8" headers with a 3" Y to maximize the flow. You should seriously consider a bigger cam also.

 

definately think the exhaust is the first thing to go......... the cam isn't small, but a 402 ci motor would definately make good use of a bigger cam. it depends on what you want to do with the car. rwhp numbers are HUGELY affected by what kind of drivetrain you are running..... a little info on that would be helpful for guessing those numbers. if you're running a 6spd through an aluminum driveshaft and stock 10 bolt... i still think you wouldn't see 500 at the wheels. upgrade the exhaust and you might see 500... go with a bigger cam and get the 510+ you want.

 

My guess is you will see about 415 RWHP. If you upgrade to Kooks stepped LT's, ORY, and a hi flowing cat back like a magnaflow you'll probably pick up another 75 HP for a 490+ RWHP number.

 

75 HP by switching from mid length headers to full length, and switching muffler type ? that seems like a lot. I was thinking maybe 10-15 for full lengths and 20 for muffler type. I did try to run with an off road Y pipe and it was soo freakin annoying. There was a nasty resonance/buzzing at about 2500 rpm. Very annoying. I dont mind louder but that was annoying. I would like to keep the mid lengths and maybe just go to an off road Y and get a muffler without that damn resonance. I just dont want the exhaust to sound tinny... any suggestions on a muffler I can weld in place of the flowmaster that sounds similar but flows a bit better.

 

Believe it. But you would need to not only switch muffler type, but also ditch the cats and go with a larger diameter longtube, not just any longtube. If you did that and matched the cam to your combo, there's your 500 RWHP.

 

Any suggestions on a muffler to use without cats that wouldn't sound too tinny ? More of a deeper sound if possible.

 

Are you willing to go with a true dual setup?

 

yes, I do have access to a meineke shop where I used to manage and I could fab something up but. I would be open to consider a true dual setup but I would want to go all the way out back.
Thanks
Ron H.

 

.
425 to the wheels on a 6 speed, until you get rid of that exhaust.

And yes, the cam is kinda small for a 402.

 

I have true duals no cats with magnaflow bullet-style mufflers. Ground-shakingly deep and no rasp. If you like the sound of flowmasters, then I think a setup like mine would make you smile ear to ear.

Oh, but you absolutely positively HAVE to use mandrel bends. I had a crush bend-setup fabbed by a bunch of jokers at a Merlin and it cost me 25 rwhp. I have before and after dynos to confirm.

 

PM'ed you!