I sbc expert . I just got a 59 283 with 2 different heads , one is 3755538 an the other is 3884520 , can I run them on the same engine ? Richard
3755538 is 1955-59 GMC 283 truck head...3884520 is 1960-67 283 Chevy truck head. Both should work just fine together unless they have different CC volumes. But I'm pretty sure they are the same.
the 3755538 is a 59 283 1.72/1.50 could be fi corvette head 3884520 60-67 283/327 1.72/150 60 cc would depend on cc of the 59 head if its 60cc yes
the engine came from a 59 fire truck , and the chambers volumes is what I'm looking for . Where did you get the information that those heads are gmc and chevy truck heads , the only info I got on the 3755538 head was that there 59 FI heads . Tank you . Richard
this might help a bit http://outintheshop.com/faq/casting/heads.html the one thing about those heads unless some one had welded them up as cheater heads is it is possible early 59 one has or could have staggered lower valve cover screws the other straight up and down, chevy had a change in the patterns in the time area of those heads 3755538 283 59 1.72/1.50 250-290HP FI Corvette I don't see the cc's listed just fi vette 3884520 283/327 60-67 1.72/1.50 60cc
I was gonna say...the valve covers won't match. You have the heads sittting in front of you, do they look the same? or different?
I got that engine off of a fire truck whith those heads on and are still on . It was running whith those heads for a long time .
It'll run with different heads. It might not make the most power that it's capable of. If the heads are both power packs (have the little triangle on the front), then they're probably close enough that it'll work fine. The early power pack heads are worth some money, if you end up rebuilding the engine, and it would look ok with the 520 heads on it, you could find another one, then sell the early head to a vette restorer guy.
1960 was the change year for the valve cover bolt pattern so they should be 2 different covers ,UNLESS some did as we did in the past and nickel rod welded the lower gasket rail up and over so the late on early wouldn't get caught at tech inspection . his photo of the engine is not good enough to see the valve covers and their bolts till he can we can only point him to where the casting numbers he gave us lead's us 2 different heads but looking closer at the motor, can you clean up the block numbers on the right hand boss just below the head behind that fuel line and give them to us? as from what i'm looking at the taught of a 327 comes to mind ,old 283 didn't have that fill cap and tube, 327's did
the block numbers 3756519 , it was in a 59 gmc spartan truck . at one point in time the 3884520 head was swap in place of the original. that head and valve cover are orange while the rest of the engine is green. the truck was probebly built in Canada Tank you guys Richard
The block is a 58-62 283 170-315 H.P. 2 bolt main car, truck block.The 3755538 head is a 59 283 with the same 1.72/1.50 valves but I couldn't find the CC's. http://www.nastyz28.com/sbcmenu.php
that is not the number I was thinking about that one is the vin hand stamped number stamped into the block in front of the right side head it will have a 2 or 3 letter code at it's end that tells what the motor was built as. i'm working on one that reads f12076EM the em tells it is a 1957 corvette 250 hp hydro lifter fuel injection corvette built at the flint plant dec 7 1956 chevy had some odd heads early on with the 56 cc 3731539 57 fuelie head bringing as much a $5.000 for a good pair right now information from chevy tech http://www.chevytech.com/ http://www.chevytech.info/3c3755538.html http://www.chevytech.info/3c3884520.html here is another link with good information http://www.enginelabs.com/news/quick-ref-small-block-chevy-cylinder-head-casting-numbers/
Could that be an M at the end, instead of II? M was used as a suffix code on 58-59 truck 283 engines. No Is in the old book.
The fuelie head would have a different casting mark than say a power pack head or like a double hump head. Clean the ends off and send us a pic...would tell us a lot. Tim
The 520 head was used from 1960-67 on 283s, 1962-67 on 327s. 60cc chamber. Some marked "Made in Canada". This head was also used by Studebaker.
They had the bosses on late 50s heads, and some were drilled for air compressor mounting, both on air suspension cars (of which they built very few) or for trucks with air brakes. Does that head with the holes in the end have staggered valve cover bolts? that ended in 59
pic 1 and 2 is a early double hump fuelie .pic 3 is a later power pack http://www.crankshaftcoalition.com/wiki/SBC_cylinder_head_identification
The early head is not double hump, it's two bars, they're square, not rounded on top. Looks like a truck head, on a truck engine. probably open chamber, might have different exhaust valves or something to deal with the higher heat that truck engines develop. To answer the original question, the engine probably has more compression on one side than the other, and if you were going to try to run the engine in it's original truck application, it might not last as long as it should. Apparently it does still run. I have the 1959 Chevy parts book, it lists a 3755537 head casting, but not the 3755538. And I've had a few of the 1958-59 heads with the bolt hole bosses on the ends. Looks like it's just a truck motor, that had one head (and valve cover) swapped with one from a 60s power pack engine. If you found another 520 power pack head, it would be a good engine to build for a 60s style hot rod.
early hd and hp heads used the rectangle/square single and double to indicate what they were used for. basicly this was the early form of our better known camel hump, around 1960 or 61 the double square/rectangle became what we all well know as the rounded camel hump hp head we found on 300 hp 327s with the smaller valves or the 365 /375 hp with the bigger valves , in my own rebuilding I have seen both on early hp/fuelie motors. the 57 250 hp fi i'm doing now has a single bar and this is a untouched ever motor, these heads are the 997 casting with 56 cc chambers here is a link that may help a little more.http://forums.chevyhiperformance.co...re-humps-on-sbc-head-what-do-they-meannot-th/ as to the bolt holes in the back, it has been brought up above 1958 up hd motors had this and those heads are now rare to find, where I found them was mostly on boat motors and truck motors
Back in the day no one gave a rat's ass about casting #'s… we went by the casting marks on the front of the engine. I worked at two different Chevy shops in the 60's…when we replaced a head under warranty it always had a different casting number anyway… if Chevy didn't care neither did we. I've seen 'untouched' original engines with two different heads… unless you are building a race engine match the valve sizes and cc's and run it.
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