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Discussion Starter · #1 ·
Hopefully some one out there has the info for me or knows a site where I can go... Looking for the Combustion Chanber size on the 1987 up TBI heads as well as the 1986 older style head. I'm thinking 64 cc? Anyone know... Otherwise does anyone know how big a dish the pistons have in the 86 motors and in the 87 up TBI's? Looking at some heads changes and trying figure if I can swap on the heads and be ok compression wise. Thanks



1987 Chevy K5 Blazer- 350 TBI
 

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Check with http://www.mortec.com for a possible source of head casting information and combustion chamber cc size. As a general rule, the pistons for a 350 will have about 17 cc of dish volume. If the 350 TBI heads are 64 cc (which I think they are) then the compression ratio will be very close to 9:1. It's also possible to search the Keith Black http://www.kb-silvolite.com/1toc.htm piston website for more information on various piston dish sizes vs. different head cc sizes to get an idea what you can do.
dave
 
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Discussion Starter · #3 ·
I was thinking along the same lines Dave... but was wondering if anyone knew forsure. I was at mortec before and they just don't give enough info. a number and then truck written after it leaves a lot to be desired, but going to try taking the #'s off my heads and have the guys at Harold Chev bring up the replacement part and see if there is info there. Thanks for the help... probably will have to rip it down to see if it is roller or not, but I figure the trucks lagged behind the cars again so it won't be.

1987 Chevy K5 Blazer- 350 TBI
 
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Discussion Starter · #4 ·
Well the 87 TBI 350 was not a rollerized motor...as you guessed the trucks lagged behind the cars.

Rene

 
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Discussion Starter · #5 ·
yup I pulled the cover this morning on it. Time to get serious about the Blazer... sold my baby yesterday (the 496 Stroker)to a buddy at a steal of a price for him /wwwthreads_images/icons/frown.gif, but the plus is I can still drive it anytime I want /wwwthreads_images/icons/smile.gif. That and finally can pay off some school bills, get the lift all done and maybe accomplish a few more things on the blazer /wwwthreads_images/icons/cool.gif.

1987 Chevy K5 Blazer- 350 TBI
 
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Discussion Starter · #6 ·
dave - i know youre one of the engine gurus on this board. just wondering - how do you figure compression ratio? i know my buddy is putting an LT1 in his toyota later this month and he had a shop redo the whole thing and put some hi-perf parts in it. well, they put flat top pistons in it and it raised the compression to either 10:1 or 10.5:1 i cant remember. i know a lot about motors and understand the whole compression issue i just dont know how to actually figure it out. thanks!!

Mike ~
* Earnhardt Forever *

89 Chevy K1500 - 350TBI/700R4/NP241 - 3" lift - 33's
 
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