Ok guys - I'm currently rebuilding my 1980 L48 motor, with 4 speed tranny. Here's the deal. I pretty much will be replacing everything. I accidentally dropped a piston when I was removing it and broke the side of it, the crank needs to be turned, I just found out from my machine shop that a head is cracked, etc. Good news is that the block is good. So it'll be bored .020" over and returned to me ready to go. Here's where my questions come in. I don't know what heads to get for my cam and I'm questioning the rotating assembly.

Cam: I already purchased a Comp Cams Kit (CL12-412-8) - retro-fit Hyd Roller. The kit came with timing set, springs, pushrods, lifters, and cam. I purchased this before I found out that my head was cracked.
Heads: Other threads have mentioned the Vortec heads, but they have a max valve lift of 0.475" - my cam is going to be 0.487" intake and 0.495" exhaust lift. So i don't think these will work without further modification. I found Edelbrock Performer RPM heads (#60895) that seem like they'll work with the cam, except they say 0.100" longer push rods are required, which the rods with my cam kit wouldn't be. Regardless of what heads i go with, I'll probably need to pull the springs off and put the ones from my Comp Kit on. Does anyone have any advice on any other affordable heads that would work with my cam? Or could I make these work with minimal additional cost?

Rotating Assembly: I'm also going to be replacing the rotating assembly. If I went up to a 383 assembly (such as a SCAT 9000 crank with pistons and rods) would that work well with my Cam and Edelbrock heads (if I figured out the pushrod length issue)?

In the end I'm not looking for crazy power. I'd be fine in the 300-350HP range. I just want a fun and good quality engine that could be a daily driver. I'd love any advice you could give me on a cost effective head that'll work with my cam, and thoughts on a 383 rotating assembly. Thanks!

 

No matter which heads you go with, I will warn you about additional costs.

Head gaskets for mating aluminum to iron: about $90.
ARP Head bolts for aluminum heads: about $120.
Longer pushrods, very common to go 0.100 longer: about $100
Pushrod length checker: $15

There is no need to spend $1500-2,000 on heads to go from stoplight to stoplight. Unless you are at the track every weekend stick with the middle budget heads.
The piston top will help determine which chamber size head you need. Use a compression ratio chart and work with the Dynamic C.R. That's where the H.P. is.
Shoot for 8.1 - 8.7 DCR.
ProMaxx Freedom Series aluminum heads run around $820 pair, loaded. Come in two chamber sizes and good for 0.550 lift. Check them out at Summit or Jegs

 

Thanks for the reply! Those ProMaxx heads seem like they could work for my application. I did notice they have a spring diameter of 1.27", whereas the double valve springs from my kit are 1.43" diameter. Do heads normally have enough room to put slightly larger springs in? I did see a couple negative reviews regarding the rocker studs, so I'd probably switch them out to ARP when I put the new valve springs on.

 

What kind of budget?

i don't know of anyone who wishes they had less hp after a rebuild. I have about 440 and still get 19 mpg with original q-jet, 350 ci displacement.
so it comes down to what you wanna spend really.

heads and cam are the two most important components, that can is too small for a 383 imo and just ok for a 350.
cheap aluminum heads are just that, cheap.

 

Are you willing to put headers/better intake on it? It would be hard to not do the cast scat crank kit, that torque is awful nice on the street. You feel it everwhere not just at WOT(less throttle to get the same acceleration as the 350)
May want a touch more cam..x2 on cheap stuff, some have gotten lucky I wouldnt chance it. A valvetrain failure at 35mph/low rpm can still take an entire engine out including your block.
Id choose the eddy heads, pushrods are cheap.

 

That cam will work in a 383, you just have to keep the compression down so you don't get detonation, maybe 9 to 1. It would be an engine with lots of bottom end with power signing off early in the rpm. With good heads it will still make way more power than you had.

Mike

 

Not to flame you but the cam is really the last part you should choose. Once you have bore, pistons and heads assembled you can measure volumes for an accurate compression ratio calculation. Then you can select a cam to be compatible with the long block andgearand gearing you have. It's much more expensive to buy pistons and heads to match a $300 cam than buying the cam last.

So now you need pistons and combustion chambers to make the correct compression ratio for your cam. You need to slow down here and do some mock compression calculations to select head chambers and piston volumes.

Good luck.

 

Vortec with a 350. If buying aluminum go better than Eddy. AFR, Brodix pricier. Profiler-not to be confused with pro comp are a cost effective alternative. Buy bare heads and buy your own valves. You can get .050 more out of Vortecs pretty easy. Shave the intake guide a bit shorter by hand with a right angle grinder or Dremel. Cut a little Measure. Repeat. Run no exhaust oil seal and exhaust picks up about .100 in breathing room.

 

Take a closer look at the spring pockets by clicking on my profile, then photo album about my build. Your springs should fit easily.
ProMaxx offers three choices of spring diameters and three price ranges for those seeking higher lift cams. Their smallest spring, as I recall, is good for 0.550 lift then it goes up from there.

 

Well unless you have tried ProMaxx or know someone who has had issues, I guess you shouldn't bash their name. I have had wonderful luck with them and the machinery is excellent. Some people confuse the name with Profiler or Procomp. Different companies. ProMaxx was the former Patriot Heads. Nothing wrong with them. They flow well, have enough meat in the casting that the rocker studs do not punch through the ports. That's more than you can say for those $1500+ heads.

Eddys heads and others are $1200 plus accessories. OP stated he was on a budget and like I said, you don't need expensive heads for occasional street use, seldom track use.

 

You may be able to get more lift from the Vortec heads by swapping springs or retainers.

 

I appreciate everyone's replies. HeadsU.P. : your build looks great! I'll try to reply to all the posts here. As far as intake and headers, I do plan on completely replacing the exhaust with aftermarket. I'd like to go with sidepipes, I've always loved there look. I'd replace the intake as well. It's not that I don't want to spend money, I just don't need a crazy powerful car for stoplight to stoplight. I don't intend on taking this to a track at all. I'd more likely drive around with the AC going and my lady next to me. With that said, I don't want to get destroyed by a Kia either.... I agree with cardo0 that I shouldn't start with the cam. I hadn't intended to even replace the heads until I found out one was cracked. I was just going to have a valve job done, and keep it pretty much stock, and switch to the hyd roller cam kit. Now that I found I need significant more work than expected, I'm rethinking the process and deciding how far I want to go.

 

I searched the bad review about the ProMaxx rocker stud you mentioned. The buyer claimed that a rocker stud was loose and all of them had to be replaced with ARPs on his SBC. The buyer goes on to say that the rocker studs were inferior to his former heads and were too small. He then enclosed a picture of his old rocker studs. Which was a Big Block Chevy rocker stud. Some people!?!? Go figure.

In all fairness, I did have one rocker stud that refused to torque down after I adjusted a guide plate on my ProMaxx- 2169s. I called ProMaxx tech-line and within two days I had three brand new studs, free of charge. (The threads of the bad stud were a little wonky) **** happens.

Because all factory workers are in a big hurry to get production numbers out, I bet the guide plates are set "roughly" with a air impact wrench, for speed of assembly. Having said that:
It wouldn't hurt to pull all the rocker studs and apply Loctite Blue on the threads and reset the guide plates with the pushrods in place. That's just good common practice with any heads.

 

 

I tend to plan everything out before I build or buy anything. Being I always do my own heads, I have everything CCed out and have flowed the heads, intake, etc... before I have a cam ground. Having said that, he already has the cam kit and it's not hard to dial in the compression ratio to match. I would say buy the best heads you can afford. Also if I was in your situation, I would add 1.625 rockers for the intake side to get the lift up to .527". A good set of heads will be flowing pretty good numbers by that lift. You'd be surprised at the power you can make with good heads, moderate lift and mild duration. The better the heads are the less cam you need. Also make sure you get the squish/quench setup tight to aid in detonation prevention. .035" is what I would shoot for.

Me, I like compression, so I wouldn't build a 9 to 1 engine for myself, but I have built them for customers who were very happy in the past. I say in the past, because I don't do customer work anymore.

Mike

 

Very true. Good lift on both the intake and exhaust is a good idea.If It's a roller cam use it to it's full advantage. More lift in a shorter duration. Good power with good manners.

I don't see any specific problem with those Promaxx heads, it's just I've kinda learned the hard way that the price you pay usually reflects the quality you will receive.
Buy them bare, get them checked out, any issues fixed, set up your own valve train and I think they would perform very well for less $$ that an equivalent set of AFR's.

 

The Patriot heads flow well and did very well in the SBC budget HotRod shootout a few years back. https://www.hotrod.com/articles/ccrp...head-shootout/

The Jegs heads in the article were the 185cc Jegs rebranded Profiler heads (made in the USA). Jegs now has a special 180cc casting that would be better if you're going to keep the tiny baby comp cam from your kit.
I believe the spring pockets are way oversized and would accommodate your springs, but you should double-check (I bought the 195cc dual spring version with 1.440" spring and they had room to go up to triple springs, if desired.)


I tend to agree with everyone else that that cam is just too small for a 383; why run out of power @ 5,000 RPM?


Adam

 

For the power levels you are looking for, I would buy the best aluminum heads you can afford (do not skimp here), moderate lift roller cam (.525-.560 lift) along with a decent compression of around 9.5-10:1 with the 350/355.....I would definitely skip the 383 unless you are looking for big Gross HP (over 450 GrossHP which you are not). A 400 Gross HP 355 will have all the torque that you seem to be looking for and will move the car easily with very little throttle. My L-82 355 with AFR heads, Roller cam (.525 lift) along with 10.2:1 Compression is never at a loss for torque on the street with my 4 speed and 3.70 gears in any gear.

 

For many of us the problem is separating the good parts from the unusable.
Then there is our goals for power.
Many times we want to hang onto parts that are incompatible w/rest of combo.
Then there is the budget, if there is one? lol

There is nothing new about a SB!
Use the search and try not to put the cart ahead of the horse.
Lots of good advice here.

JMHO

R

 

I've been running some compression numbers.

Based on the posts and additional research, I think I'll leave it at a 355. No need to stroke it.
4.03" bore
3.48 stroke
64cc head (Either the ProMaxx or Edelbrock - still deciding)
Keith Black KB193-030 pistons (dished 12cc volume)
Gasket: .041" (also could go with a .015" option)

I'm getting 9.2 - 9.6 static compression ratio and with my cam it drops to 7.7 - 8 dynamic compression. The variation is based on deck clearance and gasket thickness. The pistons are rated at 9.6 CR for 64cc head which appears to be calculated at 0 deck clearance. If I went with the thinner gasket it could be as high 10.2CR (8.5 DCR) if the deck clearance is 0. I wouldn't want to go that high.

From what I've read, 8:1 DCR is a good target to shoot for. Much higher and you run the risk of detonation.