quote:Well, 5/16" isn't that thin really, plenty thick for the torque associated with an intake manifold. You can maximize thread engagement by using National Fine threads instead of National Coarse. But it does make sizing the length of the manifold bolts rather critical. If it were me, I would probably choose to use 1/2 thick plate for the adapters, and mill the intake a bit. There is also the need for a bit of port matching, but that is rather minimal. Overall, to run a long runner 351W efi intake on Rons 9.2 Windsor block with C302 heads looks to me to be a rather straight forward thing to do. Having dual SVO & Windsor bolt holes/bosses in the adapter plate is the approach that makes this possible.
I think the adaptation of the W intake may be a little more involved. I've spent a fair bit of time with 9.2 versus 9.5 intakes and bolt patterns, but that was always superimposing a 335 series pattern over itself in those two deck heights, not a Windsor pattern. I'd like to offer the following observations and comments:
It's true, applying the 9.5 deck intake to the 9.2 will raise and help align the ports on high port heads. The bolt patterns may be a totally different matter.
I think there are two approaches to this problem and they have been previously mentioned in this thread. -Mod the less expensive intake so it properly bolts to the heads or put a second pattern in the heads.
Offhand, I'd say weld up the holes in the intake and drill them in the right place to fit the head. You might try positioning the intake on the heads such that the ports align well (this may take adapter plates) insert a drill bushing in the Windsor mounting holes, and use it as a fixture to drill and tap the heads. You'd need to check to ensure that you don't punch a hole in the water jacket (most potential for this on the holes at each end) and that the holes don't partially overlap the old pattern. If you try to put a 9.5 335 series pattern over a 9.2 pattern, they will overlap.
Though I've seen heads with two 335 series, I've never attempted redrilling heads for a Windsor because (sorry fellas) there is no Windsor intake that's interesting enough to me to justify the effort. Based upon Ron's choices of parts so far, I doubt it's a good choice for his build. But.....
Even if you were to use the Windsor pattern, won't the bolts engage any adapter plate at an angle, say 45 degrees on the Windsor pattern? If this is so, you will have thread engagement on one side of the bolt. On something as thin as 5/16", won't that side hit the head about the same time the threads on the other side engage?
Though I can only see a couple of the mounting bosses, if you examine the modified Trickflow intake in this thread closely, you will see that the pad angle of these mounting boss has been modified to the 22.5 degree angle (Midway between perpendicular and 45 to the head) of the 3/8"-16 portion of the 335 series Cleveland pattern. If you look at the flange side of that Trickflow intake, it looks nice and clean. I'd have to guess is was welded, redrilled and milled because those holes use be at a different angle and would not have broken through the intake flange in that manner.
It's a lot of work and appears to have been well done. IMO, the intake would be better suited for a properly cammed 2V headed engine.
Kelly