best head for a 318??

[powerdodge]

hello!!
I'm going to get up the compression in my 318 by milling the heads.
the problem is I have 2 heads to choose between. the original 675 head from aroud '70 and a set of 915 heads.
what is the best choice?? the car is heavy,it's a RAM, but I cruise alot!

what are the chamber size in this heads?? I can't find it
thanx!

[roadracerjeff]

No brainer. Leave the 675s on the shelf, and have the 915s milled to your desired compression ratio. 675s are 318 heads with 273/318 size ports. 915s are 340/360 heads that flow very well in stock form -but they will drop your compression quite a bit if you don't mill 'em. I would have the machine shop take the necessary measurements of your piston height at TDC, and CC the heads to find out exactly how much to mill. You'll have to decide whether you want to burn regular or premium fuel. For regular, go with 9:1. For premium, keep it just under 10:1. If you post your e-mail, I will send you a couple of articles that will help you. Lastly, you may also want to put a better intake manifold on while you're at it. Since weight isn't a big deal, the cheap route would be to get a stock 4 bbl 340 or 360 cast iron intake (check e-bay, and parts forum here). Keep in mind that if you mill heads a lot, you have to mill the intake to keep the ports lined up -all the more reason to put your 318 4 bbl intake on the shelf too (assuming you haven't already upgraded your intake.) Later,

[dave571]

What are using the ram for?

If it's for towing or hauling, or off road, ect, you may be better off with the older heads.

The smaller ports improve low end velocity/torque.

A ram is heavy, and a 318 small, so you don't want to lose any torque, if that's what your after.

[powerdodge]

my e-mail = dkrug@online.no

dave, the car is a daily driver, but I cruise a lot in the weekends! I want some show and go!
I have the edelbrock perf. plus camshaft, and performer intake.... and a carter 625 on the top.

thinking of a new converter too...

[dave571]

Then I must concur with 69gtcuda318, and say that running the bigger heads is better. Do a port match ect.

What gears are you running? It may be a little doggy down low, without the right selection of gears and converter.