I have a stock 302 motor from a 68 cougar in my 66 coupe. It currently has the cast iron 4-bbl intake and 4100 carb. I am thinking about upgrading with a new carb and intake. Any suggestions..., or should I just keep what I have?
Edlebrock Performer is pretty good. Holley is my choice for carb though.
PERF RPM manifold might give you a hood clearance issue depending on your air cleaner.
I have the performer on my 71 and the performer RPM on my '68, both with similar Holleys. The difference is noticeable and if I were racing at a track I would perfer the RPM but for anything else the regular performer is better.
I like the powerband of the performer much better than the RPM, but that is just my opinion.
The difference is dual plane vs. single plane.
The 4100 carb is a very decent piece. if it's in good shape, keep it. Why spend extra money? Next up, I'd go for the Edelbrock 500 or 600 cfm carb. Very smooth, easy to use carbs, no leaks easy to rejet.
Manifolds? What kinda driving and gear ratio do you have? With 2.80 gears and low speed driving, you might do better with the stock cast iron unit. It produces a lot of low end torque but fades quickly. Next up, I'd go for the Performer manifold it still has excellent low end torque but a broader rpm range, it would be a better choice. I'm cheap, I'd look for a good used one!
If you plan on leaving everything else stock don't go over 600cfm on the carb. Weiand makes a good intake for small block Fords. The Action Plus and the Stealth. The Edelbrock intakes seem to be the most popular though.
The mounting flange on the performer intake is so narrow you won't be able to use your 4100 carb without making a mounting plate. Huge vacuum leak. Something to keep in mind. I used a Holley 600 for years and got tired of the 14 mpg. 4100 would do better gas-wise.