Technical 283 Chevy and cylinder head question

Hey guys, I’m working on a 1951 shoebox ford coupe that the previous owner put a 283 in. I’m a ford guy so I have practically no knowledge about Chevy engines at all so I’m sorta stumbling along here trying to figure it out. The car has been in his garage for over 50 years. It had a blown 6 so he put the 283 in it. The motor is a 1967. He said it came out of a 67 full size Chevy that was wreck with 6000 miles on it. The only changes he did to the motor was swap out heads he had redone so it would have the alternator mounting hole on it. It still had the original 2 bbl intake on it, when I got it, but he gave me a cast iron 4bbl intake for it as well.
I decided to run the 4 bbl cast iron intake and a 600 Edelbrock. When I took off the intake and the valve cover everything looks brand new. I was then given another set of heads from my buddies dad that he said were power pack heads. They are in real good condition just been sitting for years under his bench. This is were I am getting confused . The heads on it have a casting number of 3970126 ,the intake has 3799349 on it date code was D-18-3 . what I saw online is it’s a 63 passenger /corvette 4bbl for 300 Hp 327. The number for the heads came up as a 327 or 350. But the years ranged from being 67-71 or 67- 79 either a 327 or a 350 depending on what website I looked at. Also the valve sizes are all listed different depending on what site as well. Last one said it was a 327- with 1.94 and 1.5. I’m don’t plan on taking the heads off the block right now since they look practically new. But I’m curious if I’d get better performance running those heads or the power pack heads(don’t have the numbers on me right now) and the cast iron intake I have. A buddy offered to give me an aluminum intake but it didn’t have the oil fill on it and it looked the same as what the cast was so I passed. Just trying to get an idea about what I have here and what I could do with out rebuilding the whole thing. Any advice or pointing of where to look would be appreciated .


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You have one great little SBC..and will get lots of technical answers..
Just out of curiosity....check to see if you have the Chevy Double Hump heads...also called Camel Hump due to the casting image on the end of the heads..Very desirable heads for the old schooler .
See Pict below.

 

depending on the overall condition of the motor, will depend on how much you get out a head swap. the power pack heads really aren't anything great, they were the performance heads when small blocks first came out. But by the mid sixties all 283 had power pack heads on it. Depending on what the power pack heads came on they could have smaller valves than what you already have. Id put the cast iron 4 bbl on it and get it running. Explore the power pack heads and see if its something you want to play with later. but id probly stick with what you have. any increase in power will most likely be almost unnoticeable with only a head swap.

 

I’ll check the power pack heads when I go work on the car tonight.


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the 126 heads probably don't give you much compression....power pack heads would help that...???

Leaving it alone and getting it running would be a good plan, but then again, pulling the heads and spending more money on it is another good plan. We don't know what your priorities are.

 

All power pac heads came stock with the 1.72 intake valve. The 327/300 head would have come with the 1.94 intake valve as mentioned.

 

not all 350 heads were 1.94, they put 1.72s on a lot of 2bbl engines.

 

You've got some nice old stuff to work with. I don't know how much you plan driving the car, but the biggest issue with all of that 60's stuff is the non-hardened exhaust seats. They got away with that due to the lead in the gas. Today's gas is hard on the old seats and they will eventually pound out. I'd run what you have for now. Should you eventually change heads, upgrade them with hardened exhaust seats before you install them.

 

It seems like I’m getting 2 or 3 different numbers depending on the sites I look at for the head casting numbers, unless there is another one I should look up? Think there was a M with an 8 under it? Can’t be sure from picture I had. The motor runs great. To be honest the only reason I swapped out the 2 bbl was when I hooked up the electric fuel pump and just did a quick test,it over flowed the carb. We try to free up the needle and seat but still did it. Plus I figured swapping to the 4bb with a 600 carb would help alittle performance wise. I think these are supposed to have like 190 HP or something. Motor looks super clean and he did say it came out of a low mile car with 6000 miles.
I tend to believe it looking at the valley. It didn’t smoke at all and runs smooth..



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I know its not what you have, but if you want to increase the compression and give you a little more power on the cheap, find a set of 80's 305 HO heads, the have a 58 cc (416 head) combustion chamber and will flow just fine for a 283, combine that with a set of SCE steel shim 283 head gaskets, and with the stock pistons and how far they are usually down in the hole you should come up about 9.5 to 1 compression. The 305 HO heads are trash on a 350, they just don't breathe. but you can almost always find a set where someone spent the bucks to get them rebuilt to put on their small block to raise the compression, only find out it they wont breathe enough on their 350 to be able to wind it up any. there are great on a little 283.

 

Is that last picture the way it looks right now? If it runs good, why mess with it? You may be doing a lot of work without much benefit, if at all. I say run it like it is.

 

Last picture is how it looks after I swapped the intakes and carb.. I don’t have the valve covers bolted down because I’m swapping the stock one for a set of finned style and the thermostat housing isn’t bolted on because the one off the 2 bbl intake doesn’t fit with this oil fill. The 2bbl oil fill is at a different angle. I’m planning to run it the way it’s set up, but I figured I’d look into the differences while the covers were off and I could see the casting numbers. Eventually I’d love to put dual carbs or tri power set up on it so I was wondering which heads I should use when I do that.


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Was it running then parked for 50 years, or owned by PO for 50. Drive it for a while and find out what else needs attention. Great project find. Loved those cars since I saw Thunder Road as a kid.

 

The 51 was bought in 1967 with a blown 6. He put the car in his brand new garage and went and bought the 283 out of a wrecked 67 impala or something. It had 6000 miles on it. He wanted a manual transmission so he bought a t 10 but it was out of an olds f 85 and had the bolt on yoke. When he tried to put the trans in it hit the floor so he stuck a power glide housing in it so the motor could be mounted properly. It has a Hurst style engine mount that bolts in the front. The motor ran but the car has been sitting with it in the same spot for 50 years. He later added the newer heads so he could use the alternator mounting holes. He said he had them rebuilt before he stuck them on. I guess he put the motor in then the project stalled, then he got the heads and did that and the project stalled again.. then it sat for the rest of the time..
This was how it was when I picked it up last year. When we removed the blocks there were 4 spots on the floor that looked like brand new concrete..


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The heads currently on your 283 are most likely 64-70 cc chambers (used in 67-71), and on a little 283, your compression ratio is probably pretty low, in the 7.5 or so range, possibly less. Power Pack heads usually had around 60 cc chambers, although some later, bigger, trucks with 283's had 70 cc chamber "Power Packs" (you don't want those) so fleet trucks could use really cheap gas. The 56 Power Pack heads had 56.5 CC chambers on 265's; just to give you an idea about the how the Power Pack chamber sizes vary. Your Power Pack heads will get you into the 8-9.5 CR range, depending on the pistons in the 283. The advice on using 305 heads is good; 601 casting 305 heads have 53 cc chambers, the 416 have 58 cc chambers. Both would bump up your CR; I'd use the 601's and not worry what size the intake valves are (1.72 to 1.84). It's really hard to build any CR with these small bore, short stroke engines (265, 283). Plus the 305 heads get you the hardened exhaust seats, not that you absolutely need them. Everyone seems too concerned about receding seats, but it's really not that prevalent. You don't need big valves/large ports on a stock 283. Ideally, swap the heads out, but it'll still run fine; it just won't be the fastest car at the cruise in. Multiple carbs on a low compression, stock cam engine, will be very disappointing, unless you're just going for "looks". JMO. I am Butch/56sedandelivery.

 

Thanks! I was kinda thinking these might have bumped the compression down. I just looked at what my buddy’s dad thought were the power pack heads ,I was given. Cleaned some dirt away and there are the numbers

Guess I’ll try to find out what these are out of..
thanks a lot for all the info. Updating it isn’t extremely important at this moment but it’s something I will probably do in the near future. I figured while it was part now would be a good time to check out the numbers and find out what I had and what I plan to do later..


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A also agree the best heads to use on a 283 and the small chamber 302 heads. However back in the day We always swapped for 327 double humps.

 

This was on the front of the old heads..



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Is the H228 the date code or am I reading those numbers wrong?


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60cc chambers

 

That engine looking like that in that car, I wouldn't change those valve covers for finned, I think it looks great with those script covers on it.

 

Thanks!


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From https://www.mortec.com/castnum.htm:
3884520....60-67...283..........Some marked "Made in Canada", 60cc chamber, also used by Studebaker
3884520....62-67...327..........Some marked "Made in Canada", 60cc chamber, also used by Studebaker

These are pretty much the same as the heads that originally came on the 283.

 

Put it together and drive it, looks like a great '51 Ford.

 

The 67/68 302 heads actually are double hump castings with 2.02 intake valves, 462's for 67 and 291's for 68, same as the hi-perf 327's. awfully large valves for garden variety 283's. Smaller 1.94's would be more appropriate.

 

thanks again!

 

H228 = Aug 22, 1968 (???). I see you have one of the 283's with a "hub" instead of a dampener, as much as the 265/283 dampeners were, not much to them. That makes me wonder if you have a cast crank also, instead of a forged one that most 283's came with. Is the electric fuel pump located in the rear by the gas tank? I was looking at your build thread; you have really been busy working on that car! I'd have gone with the BW T-10 4 speed you asked about. I had to do a double take of the bare TH-350 case in the car, with a manual trans flywheel and clutch bolted to the engine (???); what the??? The realized it was only mock up. The 66 or 67 Nova in the background in one of your photos, is almost the same color as my 56 Sedan Delivery. Anyway, cool little Ford and build. I'd sure like to have your lift! I am Butch/56sedandelivery.

 

I know it's really not too relevant to this thread but most yellow 66 Novas were painted lemonwood yellow and 67's were butternut yellow.

 

Yeah i wondered about the no dampener, and no bolt on the crank there either. I wouldnt be surrised if it had the cast crank, from what i read 67 had alot of them? the electricc fuel pump is actually mounted on the frame under the drivers door. there was already a split on the fuel line there with hose so i just added it there. The trans was just the housing, no guts. the T10 was to tall and hit the floor he said with the mount he had. he just never got around to gettign the right one. plus it had the bolt on slip yoke so getting a driveshaft was a pain.
The 67 nova is my buddys. its his garage im using at the moment. he just sold the lift a few weeks ago and the house is going for sale in 2 weeks.. so i got to get it moving to take it back home. Thanks for the comment about the 51..its coming together pretty good. hoping to have it road ready by summer.

 

the original color is butternut, its painted Canary yellow..he is talking about repainting it again, so not sure if he will go back to the stock color or the same as it is now.