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69Goody · 09-07-2005, 12:27 PM

My 69 GMC camper unit has a Small Block 400 in it...but it had a 350 originally and says so on the build sheet.
The 400 small blocks did not start production until 1970. As far as whether they were used in production or not...I'm not sure. I would not put it past as an option or custom request.
I believe my 400 small block came as an upgrade early in its life. Possibly to get a little more power under warranty without any other mods needed.

One way to tell would be to look at the exhaust ports on the heads. If they are evenly spaced, then you are looking at a big block motor. 0_0_0_0
If the two center exhuast ports are right next to each other 0_00_0 then you have a small block.
The sure fire way to tell is look for the block ID code imprinted on it.

I would tend to believe that if it were a big block 402, it would have said 402 on the build sheet and not 400. No one would under state the Cubic Inches.

09-07-2005, 12:27 PM	#8
69Goody Registered User Join Date: Jul 2004 Location: Southern Tip of OHIO 45680 Posts: 49	My 69 GMC camper unit has a Small Block 400 in it...but it had a 350 originally and says so on the build sheet. The 400 small blocks did not start production until 1970. As far as whether they were used in production or not...I'm not sure. I would not put it past as an option or custom request. I believe my 400 small block came as an upgrade early in its life. Possibly to get a little more power under warranty without any other mods needed. One way to tell would be to look at the exhaust ports on the heads. If they are evenly spaced, then you are looking at a big block motor. 0_0_0_0 If the two center exhuast ports are right next to each other 0_00_0 then you have a small block. The sure fire way to tell is look for the block ID code imprinted on it. I would tend to believe that if it were a big block 402, it would have said 402 on the build sheet and not 400. No one would under state the Cubic Inches. __________________ Only the Mediocre are always at their best... '69 GMC LWB 406, TH400, 3.73 Posi' Things I've learned from my truck...If I was an automaker, my vehicles would be overpriced, run rough, and get 5MPG.