I am ready to assemble my short block (1970 SP). I plan on going by the clearances, tolerances, etc. from the 1970 chassis and service manual. Would anybody know if any of that information has changed over the years? Thanks. axle 1320 1970 Skylark Custom 1997 Regal GS
Are you building a street only motor, or do you plan on alot of racing? I believe the general consensus is that the 'book' gives real tight clearances and most regular machinists go with too loose clearances. You need a 'happy medium'. Keep the rods and mains between .0015 and .002 and you should be in good shape. *Avoid 'high volume' oil pumps! *Order some of the double grooved cam bearings from TA Performance. *Go over to http://www.buickperformance.com/page1.htm and check out the oil passage modifications and some of the other engine related tech articles. The same clearances that most machine shops use for the Chevies, won't work for our Buick engines! Make sure you ask plenty of questions...there's several things that are 'Buick specific'. Don't be shy!
Thanks for the reply. The motor will be for street & strip and will be twisted up to 6000 RPM. It will have the right combination of parts to hopefully get it well into the 13s. Don't forget, it's a 350. I am familiar with the oil pressure situation, high volume pumps and the cam bearings. Just want to be sure nothing has changed as far as clearances go since that 1970 service manual came out.
It may surprise you to know that while almost everyone advises you to stay away from the high volume oil pump kits because of dist/cam gear wear and so on that the high volume(long gears) oil pump kits for the 350 are actually the same size as the standard 400/430/455 gears so I would assume that they would produce no more wear than the standard big block gears. I ran the h/v gears in my current 350 for hmm lets see 5 years and had no problems at all with the cam/dist gears. I did go back with a set of standard gears with a wear plate last time I had the motor out for a looksee and I still have adequate oil pressure. I would say that if your timing cover has a little wear and you cant afford a new one ,use the h/v gears for a little insurance.
I think the reaon why so many people are against the HV pumps for the Buicks, is that there have been SO MANY failures and they don't want to see anyone run the risk of ruining their motor also! Seems like anyone that actually has had success with the HV pump, is the 'exception, not the rule'!! *If you use it, be very cautious - and check your distributor gear frequently!
I thought the HV oil pump prob was a big block thing because it could mess up the distributor gear on the cam, which on the big block is part of the cam, on the 350 the cam gear is easily replaced without removing the cam... I have a timing cover that has the high volume pump on it (longer gears, spacer plate).. It was on the 70 350 thats in my car now, (no rebuild, pulled out of a friend's car, put in mine, hadn't been fired in ~ year) When i fired it up the first time, engine started on a crank and a half but clicked like mad, no oil pressure.. I think I repacked the gears and pre-lubed it, got nothing... Put on the timing cover that I had on the previous engine, (the timing cover came from the original engine and now its on its 3rd engine in my car, the only original engine part there). Gets great oil pressure, stock pump, no work done... wierd... Not sure why I didn't get any pressure with the high vol pump, one of these days i'll look at it... The stock pump, if in good condition, should be fine for most all applications, IMHO Dan
