Big block makeover help plz!

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M

Mopar383v8

Guest
Hello everyone, I have a 66 383 that was rebuilt 10 years ago but has less than 1,000 miles. I pulled it and am freshening it back up. I am plagued by my compression options.

Specs: 383 .040 over flat top silvolite pistons 1.848 comp height.
Comp xe262h cam 262/270 462/470
516 closed heads w/ 2.08 and 1.74 measuring at 83cc's w/MP valve springs.
0.020 steel shim head gasket (.015 compressed) 4.38 bore
Deck clearance is 0.07 ugh...
(Quench is .085 and comp. Is 8.74) lame

I am working with a limited budget, up to $500. The question is, should I (a) shave the heads to make the chambers smaller to bump compression and have lousey quench or (b) deck the block down .040 for a deck clearance of .030 w/ gasket = .045 quench. That should put me at 9.5 on compression w/ good quench. I would run the rocker arm shims to fix pushrod length issue.I would do new pistons but the cost is too high for me at that point and would rather build a 440 at that rate.
 
Save more money.
More compression the easy and cheap way?
Mill the heads, maybe get away with the OE pushrods. But I doubt it.
 
What are you doing with this engine? As in, what's the purpose?

I wouldn't put any effort into the short block at your budget level because, frankly, you don't have the budget to do anything meaningful unless you get free labor at a machine shop.

I'd focus on getting flow from the heads, with a fresh 3 or 5 angle valve job, do some bowl porting to blend in said valve job. I wouldn't deck the heads more than just enough to make them flat and even, getting high CR's from the 383 has anyways been problematic, without domed pistons. IQ52 has posted some of his builds of low compression BB's that would be good reading for your project.

Getting the head work done will use up your budget, without pushrods and rocker shims. S/F....Ken M
 
Yep, spend your $500 to bump the compression from 8.74 to 9.5 and gain 8 HP. Whoop-tee-damn-do! Tell these boys how the rest of the engine is put together and I bet they can get more horsepower out of it another way.
 
IQ52 said:
Yep, spend your $500 to bump the compression from 8.74 to 9.5 and gain 8 HP. Whoop-tee-damn-do! Tell these boys how the rest of the engine is put together and I bet they can get more horsepower out of it another way.
Click to expand...
There you go again,with airflow over compression..again! Excuse me,..I mean that in a favorable way,Mr Laroy....
 
It is in a heavy car with 3.23 gears. It was lower compression before and was a total dog(different cam also). was hoping to get it up a little higher while it is out for the power making potential. Its running a performer rpm intake, holley 4160 750, stock exhaust manifolds (at the moment) and a 727 with 2k stall. Thanks for the input from everyone! I think i will run it as is for a while and slowly build a 440.
 
Add some headers, and call Cope or someone for a decent torque converter(this is the big one). Get a timing light and learn how to read plugs or maybe find some one with an LM-2 or other fuel/air sensor setup.

The performer rpm and holley 750 are fine for your intended goals. S/F....Ken M
 
Best bang for the buck in your case is probably headers, advance the cam, complete tuneup including carb adjustments, and upgrade to electronic ignition if it isn't already.
 
What's a "heavy car"? How married to the 3.23s are you? I agree with the others - $500 won't get you what you need - which IMO is taller pistons.
 
EchoSixMike said:
Add some headers, and call Cope or someone for a decent torque converter(this is the big one). Get a timing light and learn how to read plugs or maybe find some one with an LM-2 or other fuel/air sensor setup.

The performer rpm and holley 750 are fine for your intended goals. S/F....Ken M
Click to expand...


You have a 2k stall convertor? I run more than that in my truck. A good converter, properly matched to your combo is invaluable. In and of itself will make you feel and be able to more efficiently use the power you already have.
 
Gawd! Those are awful pistons,why do they even make them?,..........oh that's right, lots of restored Polaras running to and from the cruises that don't want to drop the coin
for silver let alone premium. Getting high squeeze out of a 383 w/closed chamber heads is a problem? Exactly how high? The OP isn't reaching out for 12:1 here,lol! Still,
You're screwed Dude, piston-wise You're stuck unless You want to buy new ones.....get MP's porting templates for stock BB heads, a right angle die grinder and some burrs
& get busy. Check the cam timing, then get the fuel & spark dialed in....................
 
Replace the pistons with some that will make quench, bolt on a set of massaged Edelbrock heads, match a new cam to the combo and replace the torque converter with on from a top shelf company.

I'm good at spending other peoples money, but it sure would be a sweet little 383.
 
The guy has 500 bucks dudes. He can afford some make-up, not plastic surgery! Maybe he should do a 528 Hemi eh? That would make it run.
 
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