Re: How much hp will my 402 bbc produce??

rocker ratio should be 1.7 for a big block

 

Re: How much hp will my 402 bbc produce??

sorry typ-o

 

I have no idea on the power this motor will make. Need more info. Are the heads stock? What size valves? Any port work? Any flow numbers on the heads? Any idea on the compression ratio? What carb? What size headers will you be using? Not sure but the converter and cam look like abit of a mismatch.
Is this going to be a street motor? Race? Both? If this will primarily be a street car, you might want to rethink the combo. The cam you have WILL NOT be the most street friendly choice. With the combination of very large cam and single plane intake, it will be kinda soggy on the low end.

 

Holy mis-match Batman.

 

I had a .030 over 396 with a 248 @ .050 640 lift cam, closed chamber rectangular port heads
Single plane intake, 850 dp carb and 2" headers and had about 10.5-1 comp.

It was a total slug, Best 60ft was a 1.77 most were 1.8's with zero tire spin.

At 3900 pounds,3800 stall and 488 gear the best it could do was a 11.98 @ 113

Hope this helps.

 

That is a lot of cam for a small big block, and those are 1970 LS-6 large rectangle port heads. This is a 6500+ rpm cam-head setup. Depending on how much dome is on the pistons, you could have as much as 12 to 1. You will need it.

The high stall will help some, but that Monte will top 4200 lbs.

What's the intended purpose of the car? If you want something that sounds nasty and has ill manners for the local Saturday Night Cruise, and you don't mind pouring octane boost into the tank, it's perfect.

But I doubt you would want to drive it to work every day.

By the way, if those are a set of 1970 LS-6 heads, there are probably a few guys out there that would love to have them.

 

those are 1970 LS-6 large rectangle port heads.

I didn't realize those 292 heads were rect port, thought they were ovals. With those heads, cam and intake it will definitely be soggy in the low/mid range rpm's, but will rev good to 7500!

 

Ouch, my mistake. The 291 is the 1970 Rectangle Port Closed Chamber Head, the 292 head he has is a open chamber oval port from the early 70's.

That even makes his problem worse, unless he has a lot of dome on those pistons, his compression will be pretty low in conjuction with that cam. He has a 6500+ rpm cam mated up with a set of 5500 rpm heads.

It will still sound nasty, and be ill handling for around the neighborhood driving. But maybe that is what he wants.

Wasn't there a 1970 LS-6 head part number or something with the "292" designation? I have heard those heads called 292's before.

 

She will start to come into her power range about 5500. You've got an intake designed for midrange power and a camshaft for high rpm power and a CID that has no grunt. You are going to have to decide what you want out of this combo and then change the parts needed to acomplish your goal.

 

I have close to the same combo, 402 60 over which is a 414, 079 big ovals with 219 188 valves no port work, comp magnum 292h cam I think it's 248 at 50 595 lift. 38cc domes, guessing compression will be 10.5 10.75 to 1, team g with a 750 4160 carb. Forged everything, nos, 300 stall 400, 2 inch hookers. Just about to start it up and break in cam. I don't know if it's a good combo, but it's what I built. Hoping for 500 hp

 

Ditch the 2" headers quick, no good for the 396, to big, small tube headers are the way to go, you'll gain your mid range and low end back.

 

I have heard that cam in a 427 based motor and it sounds nasty. Seems like a lot of cam for a 402. I ran the baby brother of that cam in a 408 and it ran pretty good. Probably had some 11.70's in it with some traction.

 

they are .060 over TRW L2242 forged pistons...i think 10:1 comp...not sure about heads/ dome size or cc as i just purchased this motor for 1500...