318 Compression

[86FifthAve]

Hello, I have a 1986 Chrysler Fifth Avenue and I am looking to give it more power. I know that the car was built new with lower compression. I was wondering if putting on cylinder heads from an older 318 would help up the compression?

[nhdriver]

Does the car have the infamous "lean burn" system on it? I had a '84 5th ave that ran like crap til I got rid of the lean burn. It was like a different car after that.

[86FifthAve]

Sadly yes it does. The system worked great when I got the car actually now its causing it to stumble randomly and at stop lights it starts to shake cause its idling too slow. Would removing the Lean Burn give it more punch?

[bulldog426]

Originally Posted by 86FifthAve

Would removing the Lean Burn give it more punch?

does the bear crap in the woods?? i'm suprised to see that lean burn is still working on ur car, i can remember when i was a wee fellow pushing matchbox cars around my dad's shop hearing em cussing that damned lean burn %^&%, rip that %^&% out of there and let's put electronic on there, couldnt tell you how many times i heard that one....

[86FifthAve]

Haha. Yeah my dad said the same thing. He had it in his old Cordoba and it gave him nothing but trouble.

[dodger1]

Originally Posted by 86FifthAve

Hello, I have a 1986 Chrysler Fifth Avenue and I am looking to give it more power. I know that the car was built new with lower compression. I was wondering if putting on cylinder heads from an older 318 would help up the compression?

In a word, no. You'll need to swap some aftermarket pistons in to get a good start on higher compression. Best heads to go with that plan would be the '302 heads from the last of the LA318's (similar to Magnums, but still have LA intake bolt patterns and oiling systems) Other el cheapo mods to go with this plan would be a stock iron 318 4-bbl cop intake and Thermoquad from any Mopar so equipped, plus an earlier dist. and ecu with vacuum advance provisions.

[cudabob496]

http://www.popularhotrodding.com/eng...ine/index.html

http://www.moparmusclemagazine.com/t...ild/index.html

http://www.hotrod.com/howto/113_0304...ild/index.html

http://www.squidoo.com/Mopar318

[JVMopar]

If you have a 2 barrel 318 then it has a 9:1 compression ratio. Or that is what is advertised. My '85 318 that I just tore apart actually measured out to be 8.6:1.

If you don't want to tear the whole engine down. Then your only choice is thinner head gasket or mill the heads. Milling the heads will be cheaper. Using the measurements for my 318. Simply milling the heads to 60cc's will put it right at 9:1. And milling them down to 56cc and using Mopar head gasket P4120094 will put you at 9.69:1

Since you have a roller cam you might as well stick with it. Call Hughes Engines and have them help you with the selection of a cam. http://www.hughesengines.com/Index/index.php