283 engine

[Seon]

What year did the 283 engine change from the heads having the staggered pattern valve cover screws to the screws straight across from each other?

[Super(sport)Man]

I'll take a guess, and say 1958.

I've seen a few examples of '57 covers that were staggered, but I've never seen staggered ones on a '58.

[bjburnout]

58's had 'em for sure and I believe most 59's had staggered valve cover bolt holes. For quick ref: I always figured staggered were 59 and older and straight across was 60 and newer.

BJ

[CDNpontiac409guy]

I've had two 1961 283 170HP engines/cars ( Canadian Pontiacs )...
both had staggered bolts.
I think the stragight across bolts might be more associated with the "power pack" 4bbl engines.
just a thought

:p

[Loafer409]

Parts books show the same part number for 59 thru 86 so that say to me that 58 was the last year of the staggered holes...09

[bjburnout]

According to the engine casting nos. book, sometime midway thru '59 they changed to straight across. This is the way I remember it way back when they were new. I don't recall any staggered holes past '59, however CPG may be right since north of the border we quite often got the leftovers.

BJ

[Rockfish39]

1958... 55-57s are staggered... 58-67s arent

ebay item #2442224932 ...you can see some really good photos of them there...

Rockfish:cool:

[bjburnout]

All 58 and most 59 were also staggered, as I mentioned above GM changed things midway thru 59.
For example
58 head 3743056 used on all passenger and Corvette cars including fuelies had staggered bolt holes.
59 head 3755550 used similarily also had staggered holes.
Before buying any heads check out their casting nos in Colvin's Chevrolet by the numbers or the Cars & Parts engine casting nos.
to be sure what you are getting.
CPG says he had some low horse 61 283 heads that were staggered but these may have been built with older parts way up here in the north

BJ

[Rockfish39]

I stand corrected...;)

[bjburnout]

Don't stand Rockfish,
I'd rather sit down and have a beer with you, maybe at our first annual convention.........in September

BJ