i am building a 350 to replace my 307. right now i run a 16.031 with ath350 and a stock 2.73 open rear. i bought a 3.42 posi rear for my car. how much power do i need to make to run 13's with 3.42's in a full weight 72 chevelle?
this may sound stupid but i'd like to know. thanks for all the help.

Acording to this calculator (http://www.slowgt.com/Calc1.htm#HpWtSpd) You need about 300hp to run mid to high 13's at 3800#

My 1969 GTO was 4150 with me in it. Built mainly to stock specs was a 400 + .060 bore. I cleaned up the heads with a nice 3 angle valve job. I had a TH400 and a 3:42 posi. Out of 29 runs I ran a best of 14.52 @97.5.
The guy that bought it from me said he tinkered with the carb and got it to run in the high 13's. I don't doubt it.
I estimated the horsepower at about 360

I think you'll need every bit of 350hp to get your Chevelle in the 13's.

A 97.5 MPH is good for 13.7's all day with a 2.00 60 ft.

Best to find a proven combination to try to make your power, and hit it the first time. There are some great deals out there on parts (used/new) for what you are looking for as a lot of guys want to upgrade. A nice set of heads, intake etc would be easy to come by and you could build a good budget motor...probably for $1500 or less, if you look around.

I would think you would need 300HP at the crank or better -and you will always want more!! ... keep in mind that a 350hp/350 combo from the 60s was probably 220hp

ak