So, I got a smokin deal on this 1957 Pontiac 347 engine. It's just a shortblock with no heads right now but the block is bored .125 and has new Jahns pop-up forged pistons. The early pontiacs also came with steel rods and cranks. I realize the early ponchos oiled the rockers up through the rocker studs and later [65 and newer] pontiacs oiled the rockers with hollow purhrods like a chevy V/8.. I also know I can bolt the later heads on my block and if I use the later head gaskets that early rocker oiling holes will be blocked off with the gasket. What I wanna know is if the hydraulilc lifters will pump enough oil up the later pushrods to lube the rockers ok....anybody actually used the 65 up heads on a 64 down poncho engine? The newer heads have the desired screw-in rocker studs, a better choice of chamber CCs, huge valves and hardened valve seats..I really want to use a pair on my engine..or maybe even a pair of aluminum Edelbrock heads...any thoughts?
Build it nice and then sale the project, I am in need of a fresh rebuilt Rocky Poncho motor again, Ha HA Rusty
are the pistons for early or late heads? two different valve angles IIRC so it may not work. and you will have to plug the oil feed hole for the rocker oil feed. 59 - 63 heads? and the intake has to match as well.
Good point on the pistons, I'd say you should try and source some matching heads, since every time we get into this discussion about Pontiac motors and heads the water always winds up murky, at best, and usually only gets muddier...I seem to recall there are water jacket alignment issues as well, or maybe that was just between early and later intakes/heads...
Regaarding an earlier post found with the search function: the valve issue was said to be compatible as long as a guy doesn't use a cam with over .500 lift. I'd really like to hear from anybody who has actually done the swap.Another reason I'd like to use the later heads is the fact I already bought a killer dual quad setup...complete down to the air cleaners and really want to use it.
I run a highly modified pair of Wenzler Super Chief alum heads on a 1959/1960 block. I decided to simply tap and plug the oil feed hole on each deck though some say you do not need to. There should be no reason why you would have oiling problems to the rockers. It is usually the other way around, you end up with more than enough oil up there and need to restrict it on a race engine anyway. Beside valve angle, be aware that most later heads are designed to be on a larger bore engine. So, check to see if the valve clear the bore too. My heads are designed to be on a much larger bore engine and I ended up running a much smaller valve on my exhaust side to clear the bore. Inspite of the smaller valves, it has run 6.77 at 200mph so far. Steve www.pontiacheaven.org Hosting- Pontiac/Buick/Olds FALL FEST Sat Nov 28, 2009 Phoenix www.pbofallfest.org 12th annual Pontiac Heaven April 8-11, 2010 Phoenix www.pontiacheaven.org 8th annual Nostalgic Show & Go! April 11, 2010 Phoenix www.nostalgicshowandgo.org
The 389 .030 pistons I have were made with reliefs for both early and late heads. I doubt 347 pistons come this way though. I have to think before I did anything I'd try a head out and spin it over slow and see if I have clearance for certain.
So we didn't get an answer here? I'd love to do the same thing but I figured it was an impossibility. I have a later dual quad intake that obviously won't work on my 56 heads.
I thought I answered the question just fine. What do you still want answered? Also, no need almost ever for a Pontiac to have a custom pushrod. If you use later heads, use the later push rods. Always use poly lock nuts to adjust your valvetrain correctly. simple, simple. If you are still not sure of something, ask specifically and I'll answer as best I can. Steve Hosting- Pontiac/Buick/Olds FALL FEST Sat Nov 28, 2009 Phoenix www.pbofallfest.org 12th annual Pontiac Heaven April 8-11, 2010 Phoenix www.pontiacheaven.org 8th annual Nostalgic Show & Go! April 11, 2010 Phoenix www.nostalgicshowandgo.org<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> 1<SUP>st</SUP> annual Spring Chili Cook off & car show Saturday , May 22, 2010 St Johns, Az<o></o> 2<SUP>nd</SUP> annual Apache County Motorsports Day Saturday, August 28, 2010<o></o> www.apachecountymotorsportsday.org
If the water crossovers can both be removed , reuse the early water crossover, but a spacer may need to be made to raise up the intake so the ports line up. BTW there is a 56 dual quad intake on ebay .
Mine doesn't cost any extra! I have a 56 316. The dual quad intake fits the later 60's heads. In the end I would likely be better off buying the correct intake as I imagine linkage with the tranny rods would be a PITA.
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