Need Help w/ Intake Details for '67 920 Heads on '66 273

[gorgerider]

I've been struggling to find a proper after-market intake for my 920 heads (5/16" bolt holes as measured w/ caliper). Is this one-year head an unloved bastard? If I have to modify an intake or the bolt holes in the head I'll need some details.

I measured the bolt size by using a caliper on the inside of the hole, inside the threds. Do I have to measure the outside of the threads and will that be the 3/8" bolts?

Thanks for your help.

 

[Bad Sport]

To take the guess work out of it, find one of each bolt and try them in the hole.

Intake and head.

 

[mopardude62]

If they are indeed 1967 920 heads they will use a 3/8" bolt. I believe the 64-65 heads for the 273 used a 5/16" bolt at a different angle. As long as you are not mixing the early heads with a later manifold or vice-versa, you should be OK. Any 2-BBL 318 manifold should fit, if you want to move up to a 4-BBL there are several aftermarket options that offer the smaller 273-318 port size with the 3/8" bolt.

 

[krazykuda]

the 920 heads have the "standard" 3/8'-16 intake bolt thread and angle.

The 2465315 heads are the ones with the special 5/16" threads.


The best intake for that would be the Edelbrock LD4B if you can find a good used one. If not, go with a Wiand Stealth for a street motor with a square bore carb...

https://www.holley.com/products/intakes/dual_plane_manifolds/parts/8022

 

[krazykuda]

I have a set of 920 heads and just checked them, they are 3/8" bolts...

 

[krazykuda]

By the way, the combustion chambers on mine are at 63 cc after a clean up mill to make them true, not 57 cc like the books say....

 

[mvh]

If they are indeed 1967 920 heads they will use a 3/8" bolt. I believe the 64-65 heads for the 273 used a 5/16" bolt at a different angle. As long as you are not mixing the early heads with a later manifold or vice-versa, you should be OK. Any 2-BBL 318 manifold should fit, if you want to move up to a 4-BBL there are several aftermarket options that offer the smaller 273-318 port size with the 3/8" bolt.

Definitely do not try using the 64-65 heads with a later manifold. It will not seal at the ports and it will burn oil like a 300K mile junker. Ask me how I know... I have heard the other way around works, if you just drill out the holes on the manifold for 3/8, but that isn't relevant here.

 

[mvh]

By the way, the combustion chambers on mine are at 63 cc after a clean up mill to make them true, not 57 cc like the books say....

Was that after valve work? The valves on my last set were seriously recessed (unleaded syndrome) and needed new seats. But I imagine that changed the volume a bit.

 

[gorgerider]

It sounds like that extra 1/16" is the difference between how I measured it (caliper inside hole) and measuring the bolt from thread to thread on the outside.

According to this table, http://www.mopar1.us/Aengine.html , the 920 heads, both adjustable and non-adjustable, were only available in '67. I have a line on an Edelbrock 4bbl intake but I want to make sure it'll bolt up and I can get a proper gasket for it (I want to do it right the first time). I'll know the Edelbrock part number later.

Thanks for the help. Now it's on to the search for headers (Sanderson says they have one, but I don't know if it'll work w/ power steering and whether I need a smaller starter).

 

[krazykuda]

Was that after valve work? The valves on my last set were seriously recessed (unleaded syndrome) and needed new seats. But I imagine that changed the volume a bit.

Yes, I had them ported with 1.88" intake valves and 1.60" exhaust valves that I got from an old set of 360 heads, fresh valve job with hardened exhaust seats, then a clean up on the block face to true them up....