I have found a few mentions of these huge 6 cylinders 503 etc. I cannot seem to find any info on these. Has anyone ever souped one of these engines up? Any info is appreciated.
You mean the 305 V6? I have one in my 61. lots of info here http://www.6066gmctrucks.org/ check out the v12! As far as I know, nobody made speed equipment for it. It's a low revving truck motor.
Are you referring to the big truck inline sixes of the 50's? I don't know much about them, but they look physically larger and different than the 248/270/302 engines and I'll bet they are nearly impossible to find parts for... There have been a couple of the GMC trucks of the sort that would have one of those show up on eBay over the last year or so. You might ask over at www.OldGMCTrucks.com to see if anyone there knows more about those motors.
He's probably talking about the huge inline sixes. they are physically bigger, much bigger. As far as souping one up, its not really practical. They are super heavy and are designed to be low rpm torque monsters. However, there is a guy that goes some of the swaps around texas that has a 3X1 intake for one...if you see it you'll know, it looks just like a regular jimmy intake, but 4 feet long.
the 302 inliners aren't that much bigger. couple inches. I think they were used in LSR too. here's an article on putting one in a 50 Chevy truck. http://www.chevytrucks.org/tech/gmc302.htm
maybe they were industrial stuff because there were no 503cis in any regular trucks!! check www.inliners.org they are the real experts on anything inline.
I'm not talking about v6's and i'm not talking about 302s. 228, 248, 270 and 302 are all the same size, and yes they are slightly bigger physically than a chevy six, but GMC did make m***ive inline six cylinder truck motors. they did not put them in pickups. they were used in big trucks.
Yes exactly I was talking about inline motors. It seems hard to find any info. Thanks for the info so far.
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