I've had a night to think this through - so permit me to backtrack.
If all you're looking for is a single plane 4 barrel manifold that can be made to fit, you could probably make this work.
BUT
This is a trap I've fallen into and a number of us have fallen into. Honestly ask yourself, "What is my motivation to purchase this part?"
Clearly, the price is right, but realize that what you're getting is essentially a 4 barrel flange with runners that come close to your ports. If that's all you require, and are willing to put up with the work to make it "work", then go for it.
But seriously - and like I say, I've been down this road, and I've learned the hard way - ask yourself, "Is this going to be the way to maximize my engine combination?"
Ben, you've mentioned that you're looking to get this engine to live at 8,000 RPM. I'm going to assume that you'll put together the right parts to make the bottom end live, and that you'll be able to work the heads to deliver power at that mark, but if you're really serious about it, the manifold is likely the last thing you're going to want to concern yourself with.
While 8,000 RPM is right in the "sweet spot" of the advertised working range for this manifold, keep in mind that this claim is based on a set of heads that typically flow 400 cfm. Can you get your Polyheads to flow that? I'm thinking that might be a stretch.
Will your necessary modifications help or hurt the flow and the velocity that this manifold claims to deliver?
Until you know what your heads flow and what kind of power band you're going to need to achieve your goal, I think the manifold should be one of the last things you purchase.
I can't begin to tell you the number of pieces I'm sitting on in my basement, that I've binned and that I've put up on eBay over the years that haven't worked.
I think an intake manifold - specifically with respect to runner length and velocity - and exhaust headers - are the final two ingredients in making a combination work. These items, properly chosen, will allow you to fine tune the long block.
The heads and bottom end are the first priority.
Yes, $80.00 is a great price, and if all you want is a 4 barrel flange that can be fitted to your engine, then you'll be hard pressed to find a quality casting for less. And it will likely be a fun project making it fit. There's a lot of potential accomplishment in that.
But what this commits you to is building and engine around an $80.00 component that, even if finely modified to your configuration, is not likely to be the best solution.
For the 130-150 club - a good choice, and have fun. But to maximize a Polyhead, I think you're putting the cart before the horse.
Chris
Cart before the horse??? no no no. This flipping the cart upside down, setting fire to it, lashing up the horse in the midst of the flames and ridding the whole burning heap through town just to say you did it. Then selling the horse because it got spooked by the flames. The entire point of the car is to be a series of the best bad ideas I can come up with.
The SAM guys ported their polyheads till they leaked water and even then they only flowed like 360cfm. So 400CFM, never going to happen, not in a million years. I've already commit to building one of the most obsolete, over weight engines any american auto manufacturor ever produced! One with no after market and no race pedigree of any kind. It should be clear by now that I lack in totality the ability to make wise and well in formed decisions! In this case I'm purposefully avoiding it.
Getting the bottom end to stay together at 8000rpm is actually the easy part. That will be exactly the same as any small block mopar. 340 style main caps, aftermarket crank, H beam rods, nice light weight pistons and she'll sing along just fine. Probably go to dry sump oiling and external belt driven oil pump as well. It's just the easy way out in that case. Again, the lack of aftermarket components for small block mopars for anything other than drag racing purposes bites.
So asking "Is this going to maximize my engine combination" isn't what i'm ever going to ask myself. I ask myself "Is this going to end in a fatality?" If the answer to that is no then I proceed. I've lost everything I've ever entered in, no reason to start winning now!
