I have an 89 with Alum stock heads. I am getting ready to rebuild the motor as a 383. I was planning on keeping the stock heads. I am going to have them surfaced and moving to 1.6 Roller Rockers. Do I need to have them polished or anything? Are they good heads to use? What size is the chamber?

Rocket Sapp

 

I ported mine and enlarged the valves not to mention went to full roller rockers. I did not 383 it but i noticed very good power gains.The heads are 48cc and i enlarged to 56cc. My car is an 89 also.

 

I agree. Hog the exhaust WAY out, and the intake as well. Put larger valves in, and some full roller rockers (Pro magnum).

With the right cam, you'll knock down 425hp and 450+ tq on a 383, I would think.

Jut don't run a really gnarley cam in it, keep it a lower RPM motor, like no more than 6000 RPM Shift Points

 

OH, and run some decent compression. I would recommend 11:1 or so. Those aluminum heads must make more compression to make the same power iron heads will, they just dissapate heat so much faster (heat is power).

 

Sorry to post so many times, I should do all my thinking at once.

Are you going to keep the TPI on that??? I would really advise against it... It's not worth keeping on if your doing a motor upgrade. I don't think you'd make anywhere near 425HP on a tpi. Maybe 450 tq, but at an extremely low RPM.

 

Well at 48cc I am going to have to do something. The package I was looking at for the crank and pistons are at 11.8:1 with a 58cc chamber head. 48cc would put it WAY to high.. At least to high to run on street gas. I want to keep it 10 to 10.5:1 at the most. I may go NOS someday with a 100 shot. So I don't want it too high. But then again, I am more worried about the gas than the NOS right now... Paying $2.75 a gal for premium is much better than $7.50 for 104 or 110 at the race shops.


I was just told about a machine shop that I need to get my work done at here in the DFW area. I have not talked to them to see what it is going to take to get the heads done.

I am going to keep the TPI for a little while. I looked at the Mini-Ram and while it would be really cool I don't think I have the extra $2,000.00 to drop onto a Mini-Ram manafold and fuel rail.

This is what I am looking at so far.

Rotating Assembly (Crank, Pistons, and Rods) $1,950.00
Cam $125.00 to $200.00 (Have not decided on which one to get)
Timing set
gaskets
Roller Lifters $200.00 to $250.00
Roller Rockers (I have not found a set for an L98 yet, need to look)
Headers $335.00
High Flow Cats (Looking)
X-Over Pipe (Looking)
Mufflers (Flowmasters or MagnaFlows)
Chip Burn $260.00

Porting and Prepping head ( Just got refered to a company last night I have no idea what they are going to charge)

Tank, decking, and boring the cyl .30 over. (Same as the Head work, however, I may be able to do this with the help of some family that works at a machine shop.)

All of that is going to run me over $4,000.00 by the time I am done. I have set saide about $5,000.00 for the job. I may just need to wait a little for the TPI replacement. At least it's on top and I will not have to pull the motor for it.

Rocket Sapp

 

ya, that would be too much compresion for the street.... but 10-10.5 is really the minimum for aluminum heads IMHO. They don't have the detonation problem as bad, like iron heads, but that also means they don't make as much power at the same compression as iron heads. Therefore, you should run more compression, like 11:1 or so, maybe more with aluminum heads. One, because you can, since aluminum heads dissapate heat much better, and Two, because you must to make as much power.

1900 bones sounds high for a rotating assembly, unless you are not doing any assembly work yourself. I picked my crank up for 120, the rods (eagle I-Beam 6.0) for 160 shipped, and the pistons for 175.
Granted, I did quite a bit of shopping to get those prices, but Still, even paying retail prices, you shouldn't be paying more than 900-1000 dollars for everything, not including machine work.

Maybe this doesn't interest you, but have you considered going carbed? I did on my 383. I looked at the expense of a mini-ram or super-ram, and said NO! I don't have the want to spend that kind of money, when I could go carbed.
Just a thought, maybe you are not a carb kinda dude.

 

The $1,950.00 is from JEGS for the Eagle Rotating Assembly and is just for the parts. I will do all the assembly myself. Here is the text from the page of what it includes.

"Includes ESP pin fit 4340 H-beam 3-D connecting rods, std/std ESP forged steel crank, SRP/JE forged aluminum pistons, piston pins, rod and main bearings, plasma moly cast iron ring set. Fully internally balanced."

I may have to find something else though... With the 48cc chambers in the heads I think this may be too much. I am also not sure about the two part seal... It has been at least 20 years since I rebuilt a motor. And things just don't seem as simple as they used to be.


As for the carb... I thought about that but I think I would rather stick with the Fuel Injection. I just really like the way it works.

 

I believe the 113 heads use a 58cc chamber.
You can always port and siamese the stock unit and upgrade later.
May not be a bad idea to 0 deck the block, also. This will help reduce the risk of detonation. Good luck

 

Sure they are. 113 castings even though they we're on a Lingenfelter 383 and we're worked, propelled my former car to 120 mph in the 1/4 while giving me very good street performance with daily driving and perfect manners.

A lot of people are quick to jump to an aftermarket head. A stock head in the right hands can run with aftermarket heads. My old car was proof of that.

 

Your stock '89 heads indeed have 58cc chambers; going from 350cid to 383cid will only increase CR by a little under 10%. When you have the heads worked (i.e. larger valves & seats, pocket ported, smoothed spark plug boss, unshrouded intake valve, etc.) the chamber volume will increase a little, so I wouldn't worry about CR going too high for street use.

A good cam for your combo would be the LPE 219; for RRs you can't beat Comp Cams ProMagnums.

Since you don't want to toss big $$ at a new intake I strongly sugget you siamese the intake base and port the base a little. This will really increase top end breathing with little loss on the bottom end, especially since you are increasing displacement.

 

I agree that the stock heads in the right hands can do wonders, BUT BUT BUT for the same money you can buy an aftermarket set of heads then recoup 1/2 that money when you sell your stock heads. Unless you can find someone to port heads for $500-$700 bang for buck is in aftermarket. People are paying $500ish per set for 113's?