[Greg T]

I have a SBC 350 that was a parts counter rebuild. It was pulled from a cube van. It's been living in my S10 for awhile now and today I decided to make some real power. So, to find out where I was, to benchmark things, I pulled a valve cover to I.D. the heads. CRAP!!!! they are 416 heads which resolve to 80-86 305 with 1.84/1.50 valves and 58cc chambers. Now this just about destroys my plans. I would think that a parts house rebuilt would be of the 8.5 or 9 to 1 CR variety. So, where do I go when the chambers are already 58cc??

I was thinking they would be 76cc and that I could clamp a set of AFR Eliminators on there to get about 9.8 or 10.0 to 1 to go with my HR274 cam I had picked out. There must be some cereal bowl pistons in that thing. Guess I'm kinda screwed!

[Blazin72]

Are you 100% sure that it is a 350?

[Greg T]

Originally Posted by Blazin72

Are you 100% sure that it is a 350?

No. I was told it was a 350. I havent had the chance to run any numbers yet.

[carsavvycook]

Originally Posted by Greg T

I have a SBC 350 that was a parts counter rebuild. It was pulled from a cube van. It's been living in my S10 for awhile now and today I decided to make some real power. So, to find out where I was, to benchmark things, I pulled a valve cover to I.D. the heads. CRAP!!!! they are 416 heads which resolve to 80-86 305 with 1.84/1.50 valves and 58cc chambers. Now this just about destroys my plans. I would think that a parts house rebuilt would be of the 8.5 or 9 to 1 CR variety. So, where do I go when the chambers are already 58cc??

I was thinking they would be 76cc and that I could clamp a set of AFR Eliminators on there to get about 9.8 or 10.0 to 1 to go with my HR274 cam I had picked out. There must be some cereal bowl pistons in that thing. Guess I'm kinda screwed!

This is not a uncommon problem with mass engine builders, such as ATK. If the engine was sold as a 350, it should have deep dish pistons. You can check this by pulling a easy plug, and bringing that piston up close to TDC, and look through the spark plug hole at the top of the piston.

[Greg T]

Originally Posted by carsavvycook

This is not a uncommon problem with mass engine builders, such as ATK. If the engine was sold as a 350, it should have deep dish pistons. You can check this by pulling a easy plug, and bringing that piston up close to TDC, and look through the spark plug hole at the top of the piston.

Well, I know, but easier said than done in an S10. If this turns out to be the case I will need about 50cc chambers to get what I need.

[carsavvycook]

If it does not have deep dish pistons, you are really screwed. You could have a 305, and not a 350 block, crank, and rods.

[Greg T]

Thats what I'm saying. Even if it does have dished pistons I'm screwed. I just wanted to do the upper end and a good cam. But I cant if it's already a low compression motor with 58cc heads.

[lanierledford]

Now I no guru, but It looks to me like someone could fizzer how to with the piston to the top, remove a plug and put something into the cyl. that wouldn't seep passed the rings to measure the volume and could be removed without harming the engine. Maybe even a balloon installed into the cyl. and measure the volume required to fill it.
With the piston on top, and the valves closed, measure the vol., subtract the head cc's should give you close to the CI. Maybe I wrong with different CI's, pistons (concaved, flat top and domed. It maybe to hard to tell the difference even having the block casing and head numbers.
Anybody got a suggestion.

[n-gin]

Thinner head gaskets

[SSedan64]

Most good shops should have a bore scope to look through the sparkplug hole and see what type piston you have.

[oldbogie]

Originally Posted by Greg T

No. I was told it was a 350. I havent had the chance to run any numbers yet.

In an S-10 you probably can't read the block casting numbers at the bell housing flange since it's proabably under the firewall lip. But GM often puts the last three digits of the casting number on the starter side of the block between the mount and starter. Even in an S-10 conversion, these should be visable when looking up from the underside.

The VIN might still be visable on the pad immediatly in front of the passinger side head if the rebuild shop didn't take a mill cut on the decks.

Bogie

[Greg T]

Originally Posted by oldbogie

In an S-10 you probably can't read the block casting numbers at the bell housing flange since it's proabably under the firewall lip. But GM often puts the last three digits of the casting number on the starter side of the block between the mount and starter. Even in an S-10 conversion, these should be visable when looking up from the underside.

The VIN might still be visable on the pad immediatly in front of the passinger side head if the rebuild shop didn't take a mill cut on the decks.

Bogie

Thats what I had planned when I get home tonight. I'll check the VIN pad first. That should at least tell me what it came out of etc. I find it very strange that this would come from a parts store. Maybe the guy lied to me.