390 & up cid Monster Motors
5 posts • Page 1 of 1
Hi all, I just bought a Comet Capri and purchased a 390 fe to put in it. I plan to build up the motor, what tranny and rear end would you recommend that i put in it? Im not planning to stroke the motor or anything just the basic upgrades.
Ryanp, It depends on a lot of things IMO. What has it got now? What was original? How hard to you really need to run it? How deep are your pockets? What is your level of skill? Do you want it to appear original? Most 66 Capris had a 289 2 barrel, a c4 auto, and an 8" rear with 3.00 gears. A hi rise intake and a Holley, cam&springs, headers and a shift kit and 3.55 gears in your 8" will turn it into a pretty potent street performer that could maybe touch the 14s. My guess 15.5 @ 90 mph. That is faster than most, in the real world. If you must use the 390[which would be the fun thing] some things will give you trouble. 390s will fit 66 Comets but just barely. The S code Hipo 390 used in Comets and Fairlanes used heads specific to these cars[I'm told] but I doubt you have to use them. I think they go with the stock ex manifolds. You'll want headers probably anyway, which can be difficult. Bell housing, flywheel, clutch, pressure plate, stick pedal assembly, linkage, not to mention a big block toploader 4 speed and Hurst Comp Plus shifter would all have to be obtained. You might get lucky, maybe not. You will have to research the exact parts you need. There's no room for "pretty close" in a 4sp FE 66 Comet. But the search and research is half the adventure! A C6 trans is tough and easy. A built C4 with a big block bell hsing and hi stall converter will be faster. I get in a lot of arguments about this but a C6 takes a lot more power to spin than a C4. Same with the rear end. 9s are stout but so is the 8 and it's lighter and takes less horsepower to spin. The axles are the weak link but lots of 9s use the same 28 spline axles as the 8s. The 8" is good for 300 hp, more with good axles. If you break it, get a 9. You will be surprised at how tough the 8" 3rd member can be. My point is,I guess, It's fun to modify and thrash your stock components to death and then upgrade to the level that meets the need you require. To go much past that point can be a big waste of work, money and performance. A dual plane hi rise intake works real well for everything. A tunnel ram is only good at very high RPM on a real race engine. 2.80 gears suck for racing and 4.88s suck for commuting. Don't use an 850 double pumper where a 600 is called for. A good rod is well balanced from the radiator to the tailpipe. A 66 Comet Capri is a great ride whatever way you go.