Thanks again for your advice and for your time and all the other people on this site for all the information. The question I have is would you change anything? What kind of performance can I expect maybe something like a 273?I would like the sweet spot be around 70 mph and have good throttle response.

possibly, but maybe not


seriously, looking back at your post from Dec 5th.
I think that you can tweek the static compression a bit more. I run 8.5:1 in the slant in my 83 D150, I have a very aggressive ignition curve and have never ran into pre ignition issues in daily driving with regular gas. I do have a cold air intake system. My actual dynamic compression is in the 180's.

You mentioned some head porting, that is good, I would also consider OS valves. Certainly not a requirement.

I have never tuned a Holly 390, but I think I read where they can be difficult to tune, although I believe they are good when you get it right. Hopefully some one with some daily driver 4 BBL carb experience will post.

The stock exhaust manifold is what it is, I would work closely with the exhaust pipe shop to get as free flowing an exhaust pipe layout as possible. Large radius bends....
Pay attention with what muffler you stick on there. I once saw a post that compared the back pressure of various mufflers, If I can fid it I will post a link.
Not the exact post I was looking for but a lot of muffler info,,
https://www.forabodiesonly.com/mopar/th ... rs.255203/

and here is the post that I was looking for, see the chart on post #2
https://www.forabodiesonly.com/mopar/th ... vs.427769/

Concerning the cam, post back with the cam info and what you plan to degree the cam to at installation.

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Your combination will be better than stock, but not close to a stock 273-2 barrel engine, you will need more static compression for that...


To get the sweet spot at the desired speed, you will have to use a conversion calculator for your tire size, transmission (with convertor slippage), and rear gearing to
see what the rpm is at that speed and work with dialing in your cam phasing, and distributor timing to peak in that area...

thanks Dadtruck for the muffler info I currently have 2 1/4 on the stock eng it is a turbo muffler don't know brand from a local muffler shop as per cam spec. 2106r Oregon cam grinders in lobe sep 108 ex lobe sep 104 . In opens 3* btdc closes 31* abdc . Ex 37* bbdc closes -7*atdc. In 214@50 Ex 210@50 lift In 444 Ex 434 In lash .015 Ex lash .015. I was planning on 8.4 static 8.03 dynamic crank comp of 161 ? was recurvng dist using FBO systems J685s springs and plate around 30* total all in by 3200? Any thoughts? Also I have the 390 on it now have been on 20,000 miles works pretty good and gets 20 mpg on highway.

Limit by 3200 rpm is fine for your rear ratio and typical tire size for 2nd gen dart, FBO J685 is a limiter plate and no springs, FYI.