I once sold a r bolt shortblock with flat tops to a guy that was building a street rod. He was swearing by a set of 1.94 intake valve sized 305 heads (not sure what the chamber size or casting number was) I think they came of a mid 80's truck. He was gonna run about 290 deg. of duration with I think aboout .480 lift on each side. What compression ratio would a set up like this yield? It seemed like a big bang for the buck if he was not talking out of his arse. Thanks
jk

Many of the guys racing in a "stock" class, use that trick. Most 305's heads have 58cc head, and the short intake runner built a little torque. Just one of those rule benders. If you what 'out and out' HP, then no, its not a good idea. If you are looking for a little "edge" in an otherwise stock motor, then it is a cheap trick.

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Mark

1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
http://personal.lig.bellsouth.net/~racer383/

Probably about 10;1 compression, good for a high duration/overlap cam, maybe not so good for a stock cam on the street with pump gas. From what I've seen, 305 heads with the bigger valves are hard to find.

Huh, I did'nt know they made them. I know that World Products sells the 1.94's with 58cc head. But did'nt know they were a production thing. Must be rare

I have these heads on my 350. I'm not sure if you have the valve size right though. I had my valves measured 'cause they seemed to take up a lot of the combustion chamber. They turned out to be 1.84 and 1.5, which were the large version for the 305 heads which, in this case, came off an early 80's police car engine. I have flatops with a composite gasket and my compression came out to 10.6 to 1. I P&P'd the heads and put a radius on all sharp edges. This probably brought the compression down a touch.These heads were featured in a small chamber head Ford and Chevy article in a performance magazine.I run midgrade gas and 36 degrees of timing with no detonation problems. They run out of steam above 5500,but I don't spend much time up there.

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74 Camaro
350,350 new paint
No money.

Thanks guys, I'm not sure if they were 1.94's, but they were bigger than the smaller valve heads. john

Apparently the circle track guys lay a 350 head gasket on the 305's and take a carbide grinder and "lay-back the sharp edge of the combustion chamber to it, like about a quarter of an inch, then smooth everything down. A good cheap mod for claimer engines that have to be cheap or so I've read. pdq67

I built a 350 with 601 casting 305 heads I have been told that is the best 305 casting.They were pocket ported and I installed the 1.94 intake valves and unshrouded the intake and exhaust valves.I also eliminated any sharp edges in the chamber.That motor with a comp 305 S cam and 410 gears went 12.68 at 109. To me that was very impressive.But I had a good freind do the machine work for cheap. The world Product heads are a far better choice per dollar.I can only guess what that motor would have done with some good castings.

The 305 heads with the 1.94 valves came off the HO engines form SS Monty Carlo and Camaro. That is the only ones I know of. I think all others had the small valves. Anything larger than the 1.94 gets shrouded too much by the combustion chamber wall. If you try to unshroud it you enlarge the chamber and defeat the purpose of using the 305 head.

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'69 RS/SS396 pro street
427/4spd/9"