Guest Bren70 Posted February 26, 2010 Share Posted February 26, 2010 Hello folks,I'm in the middle of an engine bay & motor overhaul on my 70 MC.It's a #'s matching 300H.P. 350 car. The engine was already rebuilt & hopped up so to speak when I bought the car.I am re-painting the motor & adding afew new goodies to it to make it go a little quicker & look alot better.My main goal is to bring back the original appearance while maintaining the horses.The question I have, is there a difference between factory valve covers from reg. heads to 300 H.P. (double bump) heads? I found a set from a 69 small block and the pitch between the holes (inside to outside)is shorter than the pitch on the head. I plan on slotting the holes but I'm curious seems odd. Shawn,New Hamburg On, Link to comment Share on other sites More sharing options...
Canuck Posted February 26, 2010 Share Posted February 26, 2010 I never noticed a difference. I have a stock 70 300HP Monte and a stock 72 350 Monte and there does not appear to be a difference. I have bolted other small block valve covers (just ones kicking around, not sure what they were from) to my 70 before without problems also. Link to comment Share on other sites More sharing options...
wallaby Posted February 26, 2010 Share Posted February 26, 2010 they should all be the same; gaskets too. Link to comment Share on other sites More sharing options...
kc8oye Posted February 26, 2010 Share Posted February 26, 2010 yes they are different.. There are two different valve cover patterns for the SBC.. but I think the diffence is somwhere back in the early 50's that's why some aftermarket valve cover gaskets have 4 holes. techinically there are 3 if you include the 86+ vortec 'centerbolt' type Link to comment Share on other sites More sharing options...
CrazyDavey Posted February 26, 2010 Share Posted February 26, 2010 that's right Tim, I think they changed in the late 50's early 60's but I can't ramember the exact year. The early ones are closer together on the top holes.... Link to comment Share on other sites More sharing options...
Mo's70MCs Posted February 26, 2010 Share Posted February 26, 2010 From 1955 to the ’59 model year, small block cylinder heads had a different staggered valve cover flange bolt pattern. The top two bolt holes were closer together than the lower bolt holes. You guys are right on the money! Link to comment Share on other sites More sharing options...
wallaby Posted February 26, 2010 Share Posted February 26, 2010 You guys are right on the money! Well, not all of us. LOL It's hard to believe that with all the trivial information I carry around, I didn't know that. Link to comment Share on other sites More sharing options...
stangeba Posted February 26, 2010 Share Posted February 26, 2010 That's the thing about old cars and car parts. Keeps you on your toes. I wonder how many people think they have a 350 SBC when it actually a 305? Link to comment Share on other sites More sharing options...
CrazyDavey Posted February 26, 2010 Share Posted February 26, 2010 Originally Posted By: Mo's70MCs You guys are right on the money! Well, not all of us. LOL It's hard to believe that with all the trivial information I carry around, I didn't know that. useless information Mark...useless.... Link to comment Share on other sites More sharing options...
Guest Bren70 Posted February 27, 2010 Share Posted February 27, 2010 Thanks for the feedback,I'm not too concerned about the holes I can make'm fit wthout too much trouble.As a tool&die maker I know abit about hole positions and whatnot.I'm wondering if they are off a different GM.I've been using photos of Aaron's engine bay as a reference for the resto. Shawn Link to comment Share on other sites More sharing options...
Canuck Posted February 27, 2010 Share Posted February 27, 2010 If the holes of the valve covers are not in the same place, doesn't that also mean the indent on the sides to allow room for the wrench is in a different spot? If you are trying to restore the engine truly to stock, I would think that the correct valve covers should be easy too find at not much cost. Try Leo at Koniks Klassiks. Link to comment Share on other sites More sharing options...
kc8oye Posted February 27, 2010 Share Posted February 27, 2010 i know leo has a set of original GM valve covers hanging on the wall waiting for a buyer Link to comment Share on other sites More sharing options...
Guest Bren70 Posted February 27, 2010 Share Posted February 27, 2010 Thanks again for the response.The hole pitch is out from the intake side to the exhaust side of the cover.After looking closer I realized that they are slightly distorted,one worse than the other.So a little tweaking and I should be good to go.Other than that,they are in mint cond..Sometime I'll get some photos up on here(I'm not very tech savy).Also like to say that is a beauty couple of Montes you've got there, Aaron. Shawn Link to comment Share on other sites More sharing options...
Canuck Posted February 27, 2010 Share Posted February 27, 2010 Thanks! but you haven't seen the gold one up close, photos hide a lot of dents/chips/scratches LOL. It will be a beauty some day. Link to comment Share on other sites More sharing options...
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