383 cam advice

[66BelvedereII]

I am needing a little advice about a cam selection. I bought a 66 model 383-4 with the 516 closed chamber heads out of a Polara that had only 48,*** miles on it (really believe that is actual miles). Its runs like a top. I want to put it in the car (other motor broke conn rod and took out cam and block...uggg!) as a temporary "get it running, decent power, good sound and low budget" motor. I am planning on a full up stroker in the future but my main concern right now is restoring the body but I want it running in the meantime. I was hoping to use the 284/484 MP stick out of the old motor but the conn rod took that option off the plate. I know these arent good heads but I, at this point, dont want to spend any money working the heads over as they function fine for now. I want to clean it up, shove a cam in it, new gaskets and oil pump, paint it and put it in. I have some heavy valve springs off a 67 GTX 440 that I can swap over to the 516 heads to help the cam. (the heads on the busted 68 383 currently in car have set for 22 years with intake off and valves are rusted so I figure they are shot). It is a 3.23 727 car with 1 3/4 headers and Edelbrock TM6 intake. Really just want reasonable power and good sound. Having said all that, what suggestions do y'all have for a cam. I was considering a Lunati 60303 (3 bolt, which would require new timing chain set, I have a good single bolt set) or going back with the 284/484, or maybe the 474 MP cam. I've read as much as I can but since most dont mess with these heads, I havent found much info that is relative. Thanks in advance guys...


"So that is what that noise was?" :icon_cry:

 

[70rr-brian]

That's quite the little trainwreck in that picture!

http://www.jegs.com/i/Comp-Cams/249/21-212-4/10002/-1

Maybe that cam...I think it is close to stock 383hp with 335HP

 

[lewtot184]

383's and 400's are easy to over cam. i learned this from experience and competent cam grinders will tell you the same thing. if its an automatic trans you have to be more careful. you also need compression to run longer duration cams. if it were me a small solid would be my choice because valve lash can be juggled to help the tune-up. as far as hydraulic cams go i'd probably look at a comp cams 274xe. you don't need the lift of a 275xehl with those heads and the short intake duration will help maintain drivability. with the 3.23 gear and auto i wouldn't touch the 284-.484 with a ten foot pole. i like the engle k56/58 dual pattern in mild street engines but it does have some lift (.504 intake/.515 exhaust) and will need some minor head mods. i think the comp cams 282-.495 solid would be a real dandy 383-400 street cam, especially with a 4spd.

 

[66BelvedereII]

383's and 400's are easy to over cam. i learned this from experience and competent cam grinders will tell you the same thing. if its an automatic trans you have to be more careful. you also need compression to run longer duration cams. if it were me a small solid would be my choice because valve lash can be juggled to help the tune-up. as far as hydraulic cams go i'd probably look at a comp cams 274xe. you don't need the lift of a 275xehl with those heads and the short intake duration will help maintain drivability. with the 3.23 gear and auto i wouldn't touch the 284-.484 with a ten foot pole. i like the engle k56/58 dual pattern in mild street engines but it does have some lift (.504 intake/.515 exhaust) and will need some minor head mods. i think the comp cams 282-.495 solid would be a real dandy 383-400 street cam, especially with a 4spd.

Dont know that it matters, but the 66 383-4 is a 10.0 to 1 motor, not the low compression 383 2bbl from same year. This is sorta what lead me back to the 284/484 cam...the higher compression.

 

[Cranky]

The 516 heads may just surprise you.....especially if you can clean up the back cut behind the valves. This is true with any stock head. The factory back cut sucks to say the least and will do a lot to clean up that area. Also, the small exhaust valve hurts them too. Anyways, with stock 516 heads, the Hemi grind works pretty good.

 

[rumblefish360]

For a cm to just stick in and not care just to get it going, the 284/.484 isn't gonna make ya happy but since you have it (?) just stick it in and go.

If you want a better cam and still have it for the "Just for now", IMO, just get the OE road runner cam. It's a dual pattern cam that'll help it breath better. Your 3.23's aren't really gonna let you go with a bigger cam and be anywhere close to happy.

 

[lewtot184]

Dont know that it matters, but the 66 383-4 is a 10.0 to 1 motor, not the low compression 383 2bbl from same year. This is sorta what lead me back to the 284/484 cam...the higher compression.

true compression ratio probably isn't any better than 9.5:1, if the steel shim gaskets are used. closer to 9:1 with fel-pro gaskets. i'm firm on the 284-.484. the last time i measured one of those it was 286 degrees on the seat with a 108lsa. thats 70 degrees of overlap. needs gear, converter and headers for a 383, plus a good intake. pocket porting is a plus. i used to street race 383's. i like'em but they ain't 440's and are easy screw up.

 

[383man]

I ran the MP .484 cam in a 383 Dart and it ran good. But it had 3.91 gears and a tight TA 10" converter. It had 9.6 comp and used the Performer RPM intake and a 750 DP. Had midly ported 452 heads and weighed 3570 with him in the car. It ran a best of 12.31 @ 110.
But if I were you I would run the MP .474-280 cam as that would work good in your car. I ran that cam in a stock 340 Dart with headers and a 650 DP. Ran 13.49 @ 105 on street tires spinning. That cam really worked good in the 340 and the 383 is a short stoke eng also and I feel the .474 cam would work nicely for you. Ron

 

[rlsbee]

I have the MP.484 in my '68 Bee. There are two versions of this cam. One has 68 degrees of overlap (which I have) and there is a newer version with 56 degrees of overlap which is supposed to be much more streetable. I've never been happy with mine. I had to spend a lot of time to get it to run decent on the street. It does run well when it gets to 2500+. Changing the cam will be my next big project.

 

[Meep-Meep]

I'd be surprised if you had an honest 10:1 CR so I'd keep the cam mild. Something with 112 - 114 deg of lobe separation. .460-.480" lift, 270 duration should do nicely and keep the idle vacuum above 12 in-hg. I'd shelf the TM6 and use either a performer or a factory cast iron one - either square bore or the later TQ with matching carb. I'm running the MoPar .455" in my 440 and I like it a lot.

 

[66BelvedereII]

Thanks for all the advice guys, I really do appreciate it.