Might want to plug that vacuum port off on the front of the carb. Actually you need to hook your vacuum advance up to that port if it’s the one below the throttle blades.
350 head identification
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Vacuum advance is hooked up on the other side. Vacuum modulator for the th350 goes there. Car is sitting waiting on an electric fan relay right now but thanks for looking out 👍
3932441- 1970 Chevrolet passenger car, Nova, Chevelle, Camaro. 350/250 h.p, 1.94/1.50 intake/exhaust, 76.26 cc ("single rectangle"). These are the average heads used on the 350 for '69 & '70. The better 350 heads of that year vintage ('96-'70) are the 3927186 ("double humps", same marking used on Vette 3927187 '69-'70) & 3947041 ("right angle triangle"), used in '69-'70 on the 300 h.p with same size valves with a 63.305 cc chamber. The LT1's in Vettes (370) & Z28's (360) had 2.02/1.60 valves with the same chambers. Vette oddites with the is the 3947041 heads are they have 2.02/1.60 valves with a 63.995 cc chamber, if I remeber right the same/similar to '69 DZ 302 heads.
So these are kind of like double humps but with larger chambers, lowering compression ratio? If the numbers stamped on the front are a job number from a shop does that mean theyve been milled a little? I read somewhere that if it has these heads and a standard flat top piston rebuild (motor was definitely rebuilt) that would put me in the ballpark of ~ 9:1 compression?
They have a different combustion chamber tha the double humps so that will alter performance between the two but should be in the 9:1 range stock. But the unknown is what was done to them since there is the assume shop stamp on them so have chamber been altered, machined for 2.02/1.60 valves, a port job, what kind of valve springs, or milled? The unknown is what will make or break them being good heads or just another $100 set. I have a set of '69 dated 3947041 heads on my '70 CRE 350 that was worked on by a shop before they guy who sold them to me found them. The shop I had looked over them & found they have been ported, machined for a bigger dia, valve spring but retained the 1.94/1.50 valves. Now in theory (until get the car done & running) I have a 350 that was advertised at 300 h.p. that should hit that mark but I'll be happy with a 250 range. Until they are pulled & looked over by a good machine shop it's best to run with the idea they are stock 9:1/250 h.p. heads. Another thing you should do is look at the VIN pad in front of the passenger side head to see what that motor started life as, it should have a 3 letter code ('70 & up) starting with C for car or T for truck.
Listen to what Fleming and pagrunt have shared; they've given you good advice/information. Your initial question was for 350 head identification. While looking at the pattern on the front edge gives you some indications, the definitive way to ID heads is by researching and looking up what is stamped inside between the rocker arms. Unfortunately, knowing the origins of the heads, does no tell you what someone else has done to the heads.
My 02 cents is to figure out what you want to do and how much you can afford. All of us face this dilemma but with a plan you can achieve what makes you happy!
My 02 cents is to figure out what you want to do and how much you can afford. All of us face this dilemma but with a plan you can achieve what makes you happy!
It's nothing but a basic head - large chamber w/ a small runner - never meant to, or be for performance. Engine looks very clean - button it up and enjoy it !
Yes the 441 was the sought after large chamber head years ago. Like was said, flowed the best of bad heads, and lowered compression. My friend had them on his Nhra stock eliminator nova and ran low 11’s with them. Not by choice it was his engine combo.
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