’76 Aspen R/T Buildup

Tech Question


Dear Rick,

I am currently working on a 1976 Dodge Aspen R/T with a 4 speed manual transmission and a 360. I’ll probably go with 4.10 gears. The engine has a 474 lift and 280 duration Mopar Purple Shaft camshaft, the heads have 2.02 intakes (increased from the OEM 1.88s), and 1.60 exhausts (due to lack of funds they haven’t been ported yet).

It will be used mainly for cruising during the short Quebec summer, with an occasional trip to the dragstrip. My first question is; which manifold would you recommend while keeping in mind that the heads will be ported? Second, which carburetor would work best? I presently have the choice between an 850 cfm Thermoquad or an AFB (not the new one) and I am not interested in a Holley. Third, can the 8.25 rear end hold– if not, is there something stronger that would fit right in?

Finally, could you possibly explain what the difference is between polyurethane and polygraphite used in replacing rubber bushings for suspensions.

Thanks. Pierre Daigneault


With decent gearing like your 4.10s, I would probably go with a single-plane, of which the best is probably the Mopar Performance M-1. Still, we’re talking a fairly small engine in a fairly heavy car, so, if bottom-end torque is more important than high-rev power, go with a dual-plane. Actually, if you’re bucks-down, you could do a lot worse than a stock iron manifold!

Between the AFB and T-Q there is no question: go with the ThermoQuad.

The 8-1/4″ axle is marginal. With normal street radials and semi-sane driving, it should last a few years. With sticky skins and a killer driving style, it will be toast in a few months.

There are no stronger rear ends that are 100% bolt-in. E-body 8-3/4s are probably the closest, but you’ll probably have to weld on new perches. The most bang-for-the-buck would be a 9-1/4. One from a B-body (NON-wagon) is only about 2″ wider. If you can find some wheels with less offset you could probably live with it. On the other hand, for more tire clearance, use an A-body 8-3/4″ – but then, you’ll need custom axle shafts (Moser Engineering) or shortened C-body axles (same source) to use your “big” brakes and 4-1/2″ b.c. wheels.

Polygraphite is a trade name for urethane impregnated with graphite. Supposedly, it eliminates squeaking. No performance difference, though.

Rick E.

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