What are the 340 weaknesses?

[highwaystar]

Excellent information. Thank you for being patient. I will certainly take this up very soon. Looks like I'll keep the heads and have them install new valves, seats, seals and work in dual valvesprings. Should I stay with stock intake/exhaust diameters? Probably won't port. I'm guessing rod length for 340's are 6.123? I'm guessing stock pushrods length would work with the cams some of you suggested? Probably keeping stock rocker arms unless they're worn out. I also forgot to mention that I have an edelbrock rpm manifold and 650 holley double barrel. I'll def be on a lookout for a quality engine builder when the time comes. I just want to be well informed about mopar engines. Been a sbc guy

With that manifold and Carb and a decent converter, You are already there in my opinion. Whip up on the 350's and 302's all day. I have a stock bottom end,J head motor with a little bigger cam, running 12:50's, Now this was also geared for 1/4 mile. But for the street, You being a previous s.b.c owner, You will be suprised how little you will have to do to make power. Don't be scared to put R.P.M.'s to it. It Likes It..

 

[rumblefish360]

Aren't these 360 part numbers?

DAMN! I hate when I make that mistake.

Thanks! You sir, Are correct!


Dust-Her

YEP! Con Rods are 6.123 in length. Reconditioned prices start at more than new ones that are also lighter.

Your valves should be 2.02 - 1.60. You can back cut them or step up to Ferra race valves. Excellent upgrade IMO.

P-rods should work. Depends on whats done. Being the rocker arms are a non adjustable, the P-rods need to be a certain length. Ideally, they should depress the lifters plunger down approx. .050 (Mid way down) while the lifter is on the cams base circle.

You can replacement rocker arms from the dealer. They in the MoPar performance catolog and are listed as HD rocker arms. Also, replacement hold downs and bolts, shafts or upgraded parts for the valve train.

RPM and Holley 650? Good, done there!

 

[340Dust-her]

Awesome, thanks guys