327 Small Valve Heads

[Dan White]

My 66 (68 Camaro 327) motor currently has small valve heads (1.72" intake, 1.50" exhaust) which I believe are origional to the engine. Can these heads be taken up to 2.02/1.60 size valves? Or would I be better off with 1.94/1.50? Thanks in advance, Dan

[Joe L.]

Re: 327 Small Valve Heads

Dan-----

If your cylinder heads are GM casting #3917293 I would not recommend attempting to do anything more than enlarge the intake valve to 1.94". Even that might get you in trouble inasmuch as this casting was never used for any valve size larger than the 1.72/1.50. These cylinder heads were never intended to be a performance-type cylinder head.

Actually, rather than spending money on these heads, a better plan would be to obtain a better set of heads. 1.94/1.50 heads are very plentiful and the cores are not too expensive. Some of these can be enlarged to 2.02/1.60 without too much trouble, but if you really want to go to the larger valve size, I'd look for a set that was already that size.

[Patrick H.]

Re: 327 Small Valve Heads

Joe,

Or, better yet, if numbers and originality don't entirely make a difference, I'd buy a set of Sportsman S/R cast iron cylinder heads. These will work better than an unworked set of originals and be new to boot. Paint them orange and the vast majority of people will never know.

I looked at them closely for my 71 350/270 before I decided instead to pull an extra wrong date head out of my spares and install it on the car. I think that these are the most cost-efficient new replacement cast iron head out there without going to the Vortec heads and required manifold swap.

Of course, I went and found a correct date matched pair of heads for future use, too.....

Patrick

[Clem Z.]

Re: 327 Small Valve Heads

any SB head you install bigger intake valve you must unshroud the chamber wall next to the valve. check a 2.02 head to see a example.

[John H.]

Re: 327 Small Valve Heads

Clem's exactly right - 1.94 heads enlarged to 2.02 will actually flow LESS than stock 1.94 heads unless the chamber is machined to unshroud the intake valve; factory 2.02 heads all had additional machining around the intake valve for just that reason.