I want around at least 450/450 rwhp without the 125shot. Now...is it able for me to achieve those numbers (safely) porting and polishing my stock heads, or would it be better/cheaper for me to buy aftermarket heads like afr 190cc or higher?
I'll be staying hydraulic roller, the car will still be driven on the street but not everyday, more like a weekend street/strip car.
Gimme some advice guys, heads are the most important part, i really need some insight or suggestions.

 

450 RWHP WITHOUT THE 125 SHOT.

You will need big heads and a big cam, i doubt the stock heads can flow enough to support that level NA

 

From what I have seen... AFR's aren't going to get you anywhere neer those kind of numbers.

And neither will the best ported heads, but a good set of ported heads will be comparable to AFR's.

 

then what is the average ballpark fig of a 383 with stock comp. ported heads and a big cam worth hp and tq wise,450 asking to much?

 

Assuming that the engine in a "dyno # friendly" car and connected to a 6 speed, stock rear end, 58 mm TB, 1 3/4 headers, ORY, good exhaust ststem, exhaust cut out, electris WP, AND A DYNO TUNE I would think that Afr 195's or stock heads could make 420 or so in a 383. I know that 350's with these pieces will make 390-410 RWHP but for what ever reason, the 383's do not seem to be much better on the dyno.

A mail order tune, no cut out, smaller TB, smaller headers, stock WP, 12 bolt or 9" rear, Auto trans and/or stall will just keep chipping away at the dyno #'s and make it virtually impossible to get the 450 RWHP that you are looking for.

The 383's run better and make more torque but do not seem to dyno with as much increase as you would think over the 350. Not sure if the runner volume of the heads kinda run out and if so an AFR 210 could get ya the better dyno #'s (and probably lose some low end power and be LESS fun to drive) or if the stock intake manifold is the limiting factor. I am not sure EXACTLY why the more compression and 33 more cubes doesn't make more of a difference.

If you are chasing dyno #'s and just have to have 450 than I would suggest a pretty large cam (XE 236-242 or equivelant), 6800 RPM or so and some AFR 210's or another aftermarket head that has bee "converted" to LT1 water passages, etc. This might get you there, it might not. I do not know how much the stock intake will hurt you. Some people might have a better "recipe" but that would be the only way that I can think of getting 450RWHP, if it happens.

If you ever ride in a 400-420 RWHP 383 with a REAL FAT torque curve than you would probably be happy with it.

good luck

Nighttrain66

 

420rwhp and tq is good enough, but which would you do if you were in my shoes, pay for afr castings or port polish the stockers?

and i've ALWAYS wanted to ride in someones car that didn't just have bolt ons, that could go at least 11s or 10s like Jordan M.'s Z. For petes sake i haven't even rode in or drove a ls1 powered car. There is no F-body owner around me that i know of that would be horsepower craved enough to spend money on anything that touched the oil.

 

Ported atock castings are probably the best bet for you. AFR's are great for a blower application where the big chambers are of use in lowering CR and where the thick deck provides better gasket retention. But out of the box, they will not flow as well as a good set of ported LTx castings. To achieve the same or better results they need aftermarket porting, which makes them quite expensive. The 210 and 220cc AFR heads are really the only choice for a wild 23 degree LTx combo, but now you are talking really big bux.

Rich Krause

 

To be honest, you can't really beat Lloyd Elliott's (Nighttrain66) ported heads. I searched all over the place for decent cheap heads, I'm on a college budget. I talked to him, and when he's done with my heads in about a week, I'll have cheap, awesome heads.

 

I'm having stock heads ported for a 383 I'm doing right now for a blower motor. I'm using 2.02 intake and 1.6075 exhaust valves and should end up with close to 500 rwwhp without the blower. The guy that is porting them said he should be able to get them to flow 280 to 290 at .500 which isn't bad for these heads.

 

Alright, great i got a good ? answered. Thanks guys. Now since i'm porting the stockers heres one more big ?. Where to i send them to get ported? i don't want to start a debate, i just want someone who maybe has a great set of port polished stockers on thier motor and the name or number of the place. I've searched this before and heard good and bad things bout almost everybody including gtp. I was thinking bout nu-tek? Please someone suggest someone good from experience not from a friend of a friends Z.... hehe thanks for all the help!

 

E-mail or PM Nightrain66 in the above post. He does excellent work.

 

from what i understand, a 383 does not make much more PEAK horsepower than the 350, but, it will make more power and torque lower in the rpm band, so your "area under the curve" is much larger, resulting in a faster car.

 

Phil, SkardoM, does great work. My buddy Waswa got a set of his econo port heads and put down 412 rwhp. He will most likely be busier now though b/c of the race season.

 

Can't go work with CNC heads

 

Larry Meaux, Meaux Racing Heads Abbeville Louisiana 337-893-1541.

Does great work, I'm in the process of putting his heads on my car