383 build

[68rotbox]

hello everyone, I have a 69 runner with a 383 that i am looking to rebuild again, never let a chevy guy touch your mopar!I learned my lesson, I am looking for around 450-500 hp it will be a street car. this is what i have right now 1970 383 block 0 deck kb 400 pistons .040 over, 440 source stealth heads no port work comp 280 cam,1.5 roller rockers, edelbrock perf rpm intake, 750 demon carb . the car is a 4 spd with 3.55 suregrip. also I will be running hp manifolds with 3 inch pipe from them back. any info on this would be very helpfull thank you

[aarracer]

Have a machine shop check the valve guide clearances, spring heights etc. Check for pushrod to head clearance in head while mocking up engine.

[John Kunkel]

Originally Posted by 68rotbox

this is what i have right now 1970 383 block 0 deck kb 400 pistons .040 over,

Huh? Bored .130" oversize? Good luck with that.

BTW, welcome to the board.

[Skwerly]

I think that sounds like it should be good for 400-430 HP, or real close. 500 is quite a bit more money and work, I think, but I could be wrong.

Are you going to do any head work?

[cudabob496]

Seems like you will need quite a bit of head port work and a solid roller (or long duration) cam to get to 500hp. May want to stroke it for more cubic inches also. Talk to the guys at 440 Source.

[68rotbox]

thanks , i may have some light port work done, but funds are becoming an issue at this point. I was recommended to go with the lunati 60303 cam kit. any thoughts thanks

[Skwerly]

Are you going to bracket race this thing, or is it just going to be a streeter? If it's going to be a street car, I'd build it just like you said and add some port/polish work to the heads. A 400 HP street car is no joke, and that big block will get the job done.

[cudabob496]

For more street quickness, I'd go 3:91 rear gears. Theres a lot of quick newer cars, like the 4 wheel drive Subaru turbos. I deal with those guys all the time, and they can embarrass you (hasn't happened yet!) if you aren't on your toes, with everything clicking just right. (Latest victim, a Shelby Cobra GT500!! HaHa!!)

[DartGT66]

500 hp out of a 383 needs serious parts and high rpm. The Lunati cam mentioned above, or any hydraulic flat tappet for that matter, isn't propably going to take you even close.

[cudabob496]

As they say, there's no replacement for displacement, especially on the street, where you need the torque.
For any average performance engine, you get about 1 hp per cubic inch displacement increase.

[Moparmatt72]

I used to think the same way, but it really depends on if the newer cars you were going against were modified or not, nice kill on the cobra. I have a buddy that is pushing over 550 whp on his srt4 neon, big turbo, when I had mine I was about 400 whp. I'm back to v8 for the sound and raw power, but will be taking what I learned from my srt4 and putting it to a twin turbo v8.

[cudabob496]

Originally Posted by Moparmatt72

I used to think the same way, but it really depends on if the newer cars you were going against were modified or not, nice kill on the cobra. I have a buddy that is pushing over 550 whp on his srt4 neon, big turbo, when I had mine I was about 400 whp. I'm back to v8 for the sound and raw power, but will be taking what I learned from my srt4 and putting it to a twin turbo v8.

I agree. I'm sure most of the ones buzzing around me were modified in some way. But even the stock turbo cars like the Subaru and Mazda are 0 to 60 in 5 point something seconds, and quarter times are in the 13s. So we better have our Detrot iron in tune and maybe on a diet! Having a 3500 stall and Mickey Thompson ET radials sure saves my bacon! (It sure wasn't easy losing an srt4 once!!!)

http://www.zeroto60times.com/

[rampage_82]

Hey I've only found a couple of issues that you are going to have problems with. There isn't any way the 383 bore 4.25" will work with a .040 over 400 piston 4.38"... The cam you have I am guessing is a Comp Magnum 280... it is an "old chevy grind", but don't sweat it. While it won't squeeze every last HP out of a mopar, they acutally do run very well. Another thing I would suggest is to get a set of long tube headers. While headers do have some drawbacks (leaks, heat, harder to install) the performance you get with them far outweighs the drawbacks, especially if you can get a set of high quality (see tti) headers. With Stealth heads, the cam you mentioned, good intake, headers, and a compression ratio of close to 10 to 1, you should be able to push 450 hp, 450 Ft. Lbs Tq, out of a 383 without much issue. To get to 500, you really have to spin a 383 pretty high, and will need more cam and compression as well. Or you can cheat with forced induction. Don't be down on a 383 though, I've seen a lot of them (and have owned a few) that will run with the majority of street 440's. They are fun, tough little big blocks....

[cudabob496]

I think the heads will be most limiting.
What does 440source say they will flow?
For 450 to 500 hp, will probably need around 275 cfm on the intake minimum.

[68rotbox]

thanks guys, things changed i m going with my 440 build just makes more sense. Heres what I got 69 440 block puched .030 over o deck forged 10/10 stock crank, set of ross forged flat top pistons part # 82008, stealth heads mild porting, 1.5 roller rockers this should put me at 10 to 10.5 to 1 , I will be running a rpm duel plane intake, 750 demon. heres my question i have two cams that I am hoping will suit this build cash is getting tight, the first is the cam thats in the car now comp 280 grind, the other is a hughes 2832 bl I hoping to get to the 400-500 range. 69 runner 4 spd 355 suregrip

[DartGT66]

Sounds like a decent plan! I would run the hughes cam, you've got the CR and the rockers can handle the lift, and the heads will enjoy it. Your power expectation seems realistic to me, depending of the exhaust you should make easy 400+ hp.

[68rotbox]

i will be running my hp manifolds with 3 inch pipes back for now, plan on tti next fall. got any suggestions on lifters

[Skwerly]

Yea, that sounds more like 470+ to me. Nice combination, there.

[cudabob496]

sounds good! Make sure the cam is designed for your compression ratio.
too much cam duration can cause you to lose power. Check with manufacturer.

[DartGT66]

I built a 383 with 4.25" stroke (489) a couple of years ago. The heads were ported Stealths, intake a Holley Street Dominator and an Engle cam with 230 dgerees at .050" and a little over 0.5" lift. 10:1 CR, Demon carb, MSD distributor and stock, lihtly ported exhaust manifolds attached to 3" duals with free flowing mufflers. It made 464 hp at 4900 rpm. A switch to 1 3/4" primary headers and it made 489 hp and was wat 5-10% better through the whole range.

[cudabob496]

Ya, if your in the 500 hp area, you should go 1 and 7/8 in tube headers, and
2.5 inch dual exhaust.

600 hp area, 2 in headers, and 3 inch exhaust. I went to an X pipe too! Can feel the difference!

[Skwerly]

wow, DartGT66, that sounds like a real nice setup! Did you ever run the quarter with it? Low 12s?

[DartGT66]

No, the car really hasn't "established" yet, and will propably never see a 1/4 since hte car is near the north pole where ther eain't no drag strips expect for hte reindeers? At least for 8/12 momths a year. But here is a blog for the build up of the car; even though you propably don't understand the language pic's tell more than 1000 words... If you' interested in what's it like to eb an enthusiasist on the other side of the world, take a look, most of it is not engine related though, but this is a story of one of hte nicest 'cudas in the world and I'm proud to be a small part of it. Start from the bottom of this page; http://pprcuda.blogspot.com/search?u...max-results=20


http://pprcuda.blogspot.com/