hey guys and gals im looking for a set of 3973487 cylinder heads , they are 76 cc small valve set from 71 to 76 would like them to be from western Canada if possible
Mike Ward MB said
Jan 4, 2017
I have a set of heads from my 72 Nova SS tucked away in my shed. It would be a bit of work to get at them to check the casting number. I've been hunting around online to find a reference for casting # to year and model but can't find anything that helps.
I'm keeping them tucked away with my numbered block just because it seems like the thing to do, but I'll never use them.
The original motor came out of the car long before I acquired it. Came with the car.
I'll keep an eye on the thread and if no one else chimes in I'll dig them out and have a look for you.
Mike Ward MB said
Jan 4, 2017
Found the following, looks like I probably have what you're looking for.
3973487
1971 245 / 270 hp
1972 165 / 175 hp
1.94/1.50 valves
75.47 cc chambers
Similar to #3832441 & #3782461 with redesigned combustion chamber, addition of temperature sending unit boss, three accessory bolt holes added to end of head, tapered spark plug seat and different external identification symbol cast near the internal casting number.
The Rat said
Jan 8, 2017
I have a set from a 70's Malibu, I had them redone with double springs and new valves and guides, perhaps 2500 easy miles on them, never raced.. they are 76 cc should be able to bolt on and go.. I am near Edmonton .. I will have to get casting #'s for you..
65wagon said
Jan 9, 2017
the heads are a replacement for the small chamber hipo heads of the sixtees, I definetly need a large 76cc chamber smoggers preferably unmolested small valve, I don't want to go too high in compression on a tow truck
Tin Injun said
Jan 10, 2017
I have a set of heads originally on my 1971 C-10 Chevy 307 cid. They are quoted as 74.56 cc chambers, 1.72 x 1.50 valves, pretty close to what you want. I ran them on my 68 327 for a while and ran fine on regular gas. Maybe 10,000 miles on a valve grind. Stripped and cleaned them, lapped the valves and seats and installed new oil seals. Not sure what they are worth but was thinking $100.00 for the pair. I'm in Whitecourt, Ab if you are interested.
Fred
The Rat said
Jan 11, 2017
Casting # 's are 3970126 1.72 intake... 1.50 exhaust Dated Jan 3o, an Mar 25 .. 1970
65wagon said
Jan 15, 2017
that's a little too small for a 400 that's why im looking for 487s the 76cc is a must otherwise it raises my compression too high im already at 10.3, calculated, the reason im looking for a untouched pair is I do my own work, I like too see were the issues are to begin with. If this was a 327 its a no brainer they are easy to build a 406 its a pain because you cant use rpm to get power its the size cam and heads that make it work, and you can break parts easily
Mike Ward MB said
Jan 16, 2017
The weather has smartened up and I had to go dig in my shed for something else so while I was in there I dug a bit more to get at the heads.
They are 3973487X castings with 1.94/1.50 valves.
Good that you do the work cause they will need a refresh if you're interested in them.
Can you simply drill extra holes in the heads to align with steam holes in the siamesed cylinders of a 400? I seem to recall that you can use the head gasket as a guide and drill the steam holes into non-400 heads, but I've never actually done it. The only 400 I ever rebuilt was stock, top & bottom.
Also, do you have domed pistons, or longer rods? I thought the shorter (stock) rods of a 400 created extra piston-deck clearance that added to the head volume, effectively reducing compression ratio... I am just surprised you're getting >10:1 with 76 CC heads.
It's been a long while since I worked on a 400. The old grey matter may be confusing some of the issues....
65wagon said
Jan 17, 2017
flat top wisco pistons with two eyebrows , 5.7 rods and good math .500 lift roller cam 220 dura at 112 ls, and a really well dialed in quad, ive never run out of top end pull it buries the speedo and keeps going .good engine but I could see it self destructing in the wrong hands
hey guys and gals im looking for a set of 3973487 cylinder heads , they are 76 cc small valve set from 71 to 76 would like them to be from western Canada if possible
I have a set of heads from my 72 Nova SS tucked away in my shed. It would be a bit of work to get at them to check the casting number. I've been hunting around online to find a reference for casting # to year and model but can't find anything that helps.
I'm keeping them tucked away with my numbered block just because it seems like the thing to do, but I'll never use them.
The original motor came out of the car long before I acquired it. Came with the car.
I'll keep an eye on the thread and if no one else chimes in I'll dig them out and have a look for you.
Found the following, looks like I probably have what you're looking for.
3973487
1971 245 / 270 hp
1972 165 / 175 hp
1.94/1.50 valves
75.47 cc chambers
Similar to #3832441 & #3782461 with redesigned combustion chamber, addition of temperature sending unit boss, three accessory bolt holes added to end of head, tapered spark plug seat and different external identification symbol cast near the internal casting number.
the heads are a replacement for the small chamber hipo heads of the sixtees, I definetly need a large 76cc chamber smoggers preferably unmolested small valve, I don't want to go too high in compression on a tow truck
I have a set of heads originally on my 1971 C-10 Chevy 307 cid. They are quoted as 74.56 cc chambers, 1.72 x 1.50 valves, pretty close to what you want. I ran them on my 68 327 for a while and ran fine on regular gas. Maybe 10,000 miles on a valve grind. Stripped and cleaned them, lapped the valves and seats and installed new oil seals. Not sure what they are worth but was thinking $100.00 for the pair. I'm in Whitecourt, Ab if you are interested.
Fred
that's a little too small for a 400 that's why im looking for 487s the 76cc is a must otherwise it raises my compression too high im already at 10.3, calculated, the reason im looking for a untouched pair is I do my own work, I like too see were the issues are to begin with. If this was a 327 its a no brainer they are easy to build a 406 its a pain because you cant use rpm to get power its the size cam and heads that make it work, and you can break parts easily
The weather has smartened up and I had to go dig in my shed for something else so while I was in there I dug a bit more to get at the heads.
They are 3973487X castings with 1.94/1.50 valves.
Good that you do the work cause they will need a refresh if you're interested in them.
Mike
Also, do you have domed pistons, or longer rods? I thought the shorter (stock) rods of a 400 created extra piston-deck clearance that added to the head volume, effectively reducing compression ratio... I am just surprised you're getting >10:1 with 76 CC heads.
It's been a long while since I worked on a 400. The old grey matter may be confusing some of the issues....
flat top wisco pistons with two eyebrows , 5.7 rods and good math .500 lift roller cam 220 dura at 112 ls, and a really well dialed in quad, ive never run out of top end pull it buries the speedo and keeps going .good engine but I could see it self destructing in the wrong hands
Heads are on their way - Should arrive Monday