Sorry to jump into an old thread but this is right around the question I’m trying to figure out. My 318 is running the larger valves 2.02 and 1.60. The heads were ported a bit by the previous owner. He states he “gasket matched” the heads and intake the best he could but isn’t a “pro”. I haven’t had the motor apart to closely inspect but it does seem snappier than I would have thought. My question is this after reading this thread I’m still not sure if I should go after a set of local 340X heads and start porting etc or is that not worth the squeeze with a set of worked 318s I have? Sorry if this is repetitive just learning here.
A lot is dependent on the build itself and the target of the build. In the quote you quoted, the statement was made from a certain perspective. Without going back and trying to figure out what perspective I was making my statement from, I’ll say that the cylinder head on top should fit the builds target.
For the most part, I have found it a plus to put what some people think as t much head on top BUT a well ported head is worth a lot of power even when it seems silly to use that much cylinder head.
There is a point of which the port becomes too big for use. Where this is, is a variable point. It’s also not just the engine but the car and the drive train behind the engine. Not enough stall, gear, to much tire, a heavy car, over cammed, too big of a carb, etc….
I don’t know what the 340 heads you’re looking at are cost wise, but, IMHO, I think probably you would be better off looking at and getting an Edelbrock cylinder head. As cast, they flow about as well as a nicely prepped and mildly ported 340/360 head.
The 318 heads ported are a lot of work and it’s something I personally would not invest time into. Ported 318 heads, done really well, will flow about what a good stock X casting will with some prep. If your 318 heads are professional ported to it’s best, they will equal a nicely worked on set of 340 heads. In other words, there always a step behind.
If you’re intent on building a 318, start a thread on it where it can be discussed at length.
What are the head casting numbers u have now? I doubt anyone would put 2.02 valves into a 318 head. Kim
I’ve done a 2.02 on a 318. It’s fine.
I would not do this the way I did it 30+ years ago! J heads with a 2.02/1.60. I’d do the Edelbrock head. It would go pretty far on a 318.
