I just ran a compression check on my '69 350/300. They ranged from 125-140, is this good and what's normal? Also, the engine has 75,000 on it. My uncle changed the oil every 2,000 miles. It runs great, but every gasket leaks, I plan on pulling the engine, putting new gaskets in, a new cam, lifters, timing chain and oil pump. Does anyone know what the original cam specs are? I'd like to put in a little hotter cam, I want a smooth idle and better low end torque, any recommendations?
Thanks,
Matt

Here's the specs on your cam for a '69 350/300:

intake lift - .390
exhaust lift - .410
intake duration - 310 degrees
exhaust duration - 320 degrees
rocker ratio - 1.5
stock part #3896929
casting #3896930

I don't know what the compression shoud be, but if you plan on a new cam, contact Summit Racing or Jegs and ask their techs. Tell them what you're looking for out of the engine and they can give you recommendations of brand and specific cam. You can also contact Comp Cams, Crane, or anyone else who makes camshafts and get excellent advice, but they will logically recommend one of their own. Summit or Jegs carry all the major brands and will give you straight advice.

I believe 10% differential is normal.

MattK said: I just ran a compression check on my '69 350/300. They ranged from 125-140, is this good and what's normal?

150 with no more than 20 psi variance ... (13%)

|UPDATED|8/11/2004 6:32:17 PM (AZT)|/UPDATED|

is that a go idea to put a bigger cam in without rebuilding the rest of the motor

If the motor is okay, just replacing the cam presents no problem at all.
The only thing to watch is the cam is compatible with what else is in and attached to the engine.

vho69 said: is that a go idea to put a bigger cam in without rebuilding the rest of the motor

it all depends on how lucky you feel... i personally would check the bore wear on each cylinder and if its even near the tolerance i would rebuild. at the very least I would turn and balance the crank and install new bearings and rings.

75,000 miles doesnt sound like much but engine technology wasnt as advanced in 1969 as it is now..

that engine wasnt properly balanced from the factory.. rod and main bearings from a balanced engine with 100K miles look like bearings from an unbalanced engine with 40K.

the materials are better, the oil is better.. and you know at some point someone beat on it. little old ladies didnt buy corvettes to drive to church on sunday..

someone drove it hard, (your uncle may tool around now in a land yacht.. but what was he like 35 years ago ?)

I personally believe that adding power to an engine reduces its life.. regardless of how hard you think you will drive it.. sometimes the little devil sitting on your shoulder is more convincing than the angel and when he says something like "see that mustang, you need to embarass that kid in front of his girlfriend"....

thats when you hope and pray that hopping up your engine without rebuilding it doesnt bite you in the a$$ and leave that punk kid smiling while your on the side of the road with a spun bearing..

just my .02$

anything worth doing is worth doing right.

when you think about it.. it really isnt that expensive to rebuild if you do the work your self..

if your going to pull the heads.. might as well do a valve job.. it needs hardened seats anyway.. the valve job and new seats is a serious chunk of the machine shop labor... at this point.. spend a little extra and finish the job.. you wont have to worry about the lead content of your foot for a while.