86 318 in a 56

[TURBOGUY]

I am considering puting an 86 318 in my 56 plymouth to use as a tow car. The drive train is from an 86 5th ave. I am mostly concernd with milage and good bottom end. My questions are what gear is in the diff? Small 4 barrel or 2 barrel I also have a set of late model fast burn 318 heads (swirl port) should I use those or leave the stockers on it. I would like to use stock exhaust manifolds with duals and a cross over pipe. any tips or suggestons are aprecated thanx guys.

[Thunderstruck]

An 86 318 should already have the swirl port heads. The trans in it is about the stoutest version of A904 built, not to mention it has a low first gear. The rear axlew ratio unfortunately sux, it's 2.26. However, the 4bbl cop versions have a 2.94 Sg version that'll swap right in place. Oh yeah, your current axle is a 7 1/4, the cop axle is an 8 1/4.

I have an 87 Diplomat with the same basic setup as your 86 Donor. I added the cop axle and the low end really improved, especially with the low first gear ratio. I advanced the stock 2bbl roller cam 4 degrees and that helped too. The I relaced the lean burn 2bbl with an Edelbrock 600 cfm AFB using a stock 87 4bbl cast iron intake. The ignition is handled by teh MP electronic ignition kit. I get about 18 mpg driving around with my AC on, 20+ without it. I've gotten as much as 25 mpg in colder weather. I am still running the stock everything smog related, EGR, air pump pre cats, cats, yadda yadda. Without all that stuff I might do better.

I've towed my 38 Plymouth coupe with it, on a trailer. I towed my 89 Voyager 180 miles with it, on a dolly. No problems, plenty of power, Oddly enough I go slightly better mileage towing the minivan back than I did going up with an empty dolly.

So yeah, your combo has potential and if you decide down the road that the 318 doesn't have enough lowend grunt a 360 swap is only a wrench turn away.

Steve

------------------
38 Plymouth P6
65 Plymouth Barracuda
87 Dodge Diplomat
89 Plymouth Caravan
96 Dodge Neon

"No quarter asked, none given" - Thunderstruck Racing