CafnutS007

Guys I'm installing this setup at https://mbenzgram.com/collections/al...86-top-end-kit

I have a 383, 4 barrel setup.


What exhaust I should choose or keep the original exhaust?

I thank you all for your time and attention,
Ed

Archer

Ed -

Edelbrock makes good stuff and a generic answer would be headers with 1 3/4" primaries dumping into a 2.5" dual exhaust, BUT ....

What are the cam specs?
What tranny (and stall on the converter if an auto) and what differential ratio?

Archer

Lostviking

It would be silly to invest that kind of money, and put the stock cast manifolds back on. But Archer is correct, what is the application and what other changes have been made. Compression, cam, gearing. It all needs to be considered as well as application.

RacerHog

What ever headers fit that you can find with 3" or 4" collector.....
2-1/2" tubing with some 40 or 44 series mufflers should work more than fine.
Top all that off with a Holley 780cfm or 850cfm

Just my 2 cents

CafnutS007

Thank you very much; I'll check the specs.

CafnutS007

CAM Specifications are at https://www.jegs.com/i/JEGS+Performa.../7194/10002/-1

Tranny is the standard 727 however, still checking to see if my diff is either 3.23, 3.55 or 391.

CafnutS007

CAM Specs - https://www.jegs.com/i/JEGS+Performa.../7194/10002/-1
Tranny Specs (Auto) - https://shiftsst.com/blog/post/charg...1966-1970.html. For the stall I will assume a range that supports up to 421 HP engine or a range between 400-450 HP.
Diff Ratio - I have a 8.75 diff and 3.23 gears

Iowan

I can't believe the price of cam and lifters, wow.....

RacerHog

I agree... The whole market has gone nuts in pricing !!!!

Archer

Ed -

You're good to go.

Archer

CafnutS007

Can I up my gears? Perhaps 3.55 or 3.91, these gears were optional in 1970 for the Bee. I actually drive my classic cars as much as my daily driver. I drive locally and interstate. So I want to be able to do both. On the other hand, if changing my gears will affect my local and highway driving then I'll leave the 3.23.

Iowan

With that cam I'd be thinking 3.91s and yes they and the cam will kill gas mileage.

Archer

Ed -

There are plenty of gear ratio/rpm/mph calculators on line. Plug in your gear ratio(s) and see what your rpms will be at different speeds.

I ran 3.23s for decades, but switched to 3.91 a few years a go. Noticeable difference in acceleration, but yeah what Iowan said.
It's not only gas mileage, 3.91s will limit your highway cruising speeds, unless you consider an over drive unit.

For what you're describing, 3.23 or 3.55s should be optimal, and if you have 3,23s. going through the expense to get to 3.55s, isn't worth it. IMHO anyway.

Archer

CafnutS007

Thank you very much!

CafnutS007

Iowan,

Is my CAM to aggressive? I was looking to get that nice lope sound and to add some more HP because I'm adding A/C. I don't want my car to shake. Just looking to have something in the middle of the road.

Thanks,
Ed

Iowan

I've got a cam in my 64 Fairlane that is comparable to yours but it's a solid with more lift, my compromise gear was a 3.73, forty years ago I would have gone 4.10 or 4.30s with 4.30s being optimal. If your going AC, maybe power brakes and power steering a cam with 225 degrees of duration at 050 lift is where you need to be.

CafnutS007

CafnutS007

CAM specs attached. My duration is 050 however, duration is longer.

Iowan

There is quite a difference between 225 and 238/ 246@050 lift, that 1000 rpm idle is pretty much the idle this cam will need.

CafnutS007

Can anybody chime in for the right CFM carburetor for this setup?

CafnutS007

https://www.jegs.com/i/Edelbrock/350/2086/10002/-1

Archer

Ed -

Opinions will vary:
750 (Holley double pumper) for drive-ability
850 (Holley double pumper) for max HP

Having run both, I'd go with the 750.

That's a good cam choice, for a street car 10" of vacuum is about where you want to be.

Archer

CafnutS007

Archer,

Thank you very much.

Ed

RacerHog

I Agree !!

Iowan

Do you have a stock converter?