I got my 72 350 yanked out and sent to machine shop mechanic trying to get 10.5 comp on the motor but can't find pistons unless you get a custom set running about 800-1000... So I got on board everybody is saying get set of 9.5 comp pistons and deck and mill block and heads . I tell them this and he says he can't locate a spec sheet for my Buick 350 haven't done one in a while... Does anybody have a shop that they have had their motor decked and milled at number so he can call and get me where I need to be without so much trial and error pls thx in advance
You can get flat tops any compression height from competition components for 650.00 with rings. http://www.buyracingparts.com/pisto...utotec-forged-350-buick-flat-top-pistons.html
My 2 cents worth of advice would be to take your parts and RUN! If a machine shop is all ready having problems, and its just information based ones & lack of Buick info, LEAVE, they are not the shop to build your Buick engine.
This! Determining how much to mill off of blocks/heads to achieve a certain cr is not all that hard to do and should be routine for any machine shop worth their salt. I'd say consider yourself lucky you got an early warning, grab your parts and thank them and move on down the road.
Get 85 Buick century 3.0 pistons (there are flat tops samespecs as 350 otherwise) with .035 off block will net about 10.5 with 58 cc head. That would put piston .055 below deck. Part # s1734 from summit.
What are your plans as far as cam and heads? You will need to measure valve clearances and TA big valves with porting is where most of you power will be obtained. If using a TA intake you will need to port that also. This piston combo has been used before with success by Engine builder Jim Burek.I actually have 6 of these in standard bore but going forged due to custom rods that have smaller piston pins. You will need to drill out oil passages from sump to oil pump to 1/2 minimum and 9/16 if at all possible. Then get a 5/8 pickup tube. This will supply enough oil to pump without loading front can bearing since that where pump is driven.
Auto machine in st. Charles heard good things about this shop but apparently hasnt done any buicks in awhile.....is that going to be a big dealou:
while some machine shop rules-of-thumb hold true for any rebuild , buick motors ( like others - olds , mopar , Pontiac etc ) have different characteristics and needs . cam selection , clearances for instance and certain "tricks" to get the most out of the motor AND be dependable . a buick experienced builder will put you a leg up and let ya sleep a little better . lay out your game plan , outline your budget and direction , do your homework . and be realistic with your expectations and actual driving style .
Can't remember name but a turbo Buick shop in sleepy hollow is good . if your mostly street or you get him the info he needs you should be OK.what did you plan that you need such hi compression?
I really didn't plan it I was just going to swap out cam with TA 284, stage 1 springs, double roller timing chain and be done when the rear bearing dropped. So since had to get those machine pressed thought it was perfect time to up comp on motor and have heads smoothed and polished ... Mechanic said this is time to swap pistons out and need to get the most out it by doing 10.5 and still run pump gas that's when we found out about limited forged pistons and comp roughly being 9.5 highest or you need custom order to get higher comp on pistons... Or we were going to have to deck and mill block and heads to achieve this...how much gain is to be made really from 9.5 to 10.5 at .40 bored over with this set up
the 9.5 might be a little more pump gas freindly . as to whether there is a big dif between 9.5 and 10.5 with your combo someone else can answer that better . and one big dif at the machine shop will concern the heads . sbc = pedestal mount rockers , sbb = shaft mount rockers . totally dif and with the buick non adjustable rockers valve stem height and pushrod length are very important . if the shop is 'thinking" sbc when they set it up it could cause problems . also any port/bowl work will be dif due to flow , port shape etc . also oil pump and bearing clearances , cam bearing style and positioning .
Its all a combination. What your static compression is with a cam versus dynamic compression. Even at 9.5 you can have a cam that increases cylinder pressure to the point of needing higher octane. So your cam could become less responsive with lower compression. As most make the mistake of putting too large of a cam into an engine and complain no drivability. No power off line no mpg.
Talk with them about block oil mods. I would at least drill out oil sump passage to minimum 1/2 . then get the melling pickup screen which is 5/8.
What about heads I got them polished and smoothed can't afford porting angle valve yet but they are 2bbl heads should I. Be looking for 4bbl heads or will 2bbl heads be decent until I can port
