I have a motor I picked up for a streetrod project.

In checking the numbers it is an 1985 350 cu" truck block, but it has heads with casting # 14014416 which are 80-86 305 cu" with 1.84" intakes.  Not sure of the head cc's.

Can anyone give me the low down on these heads and how they may or may not work on the 350 block.

I'm running a 260/268 adv dur. cam with 114 lobe separation  

a lot of rebuilt 350s have been assembled at rebuilders with 305 heads...

there are a lot more 305 heads than 350s available...

most of the time they install special pistons with reduced compression to make up for the differnce in chamber volume..

others will have more info... so be patient.. and post the block casting number if you can... if the oil pan is off... see if you can read the casting numbers on the pistons with a flashlight...  most have them...  

The heads have 58cc chambers and should work well on the 350.  

I have concerns with compression ratio.  Engine is together & running in car.    This may sound silly, but could I get a relative idea of whether C/R is excessive by taking a compression test?  

The block casting is a "207" 350cu.

In peeking thru the the plug hole, it "definitly has dished piston, but obvoisly can't determine dish cc's.  

do you have the ability to crank the engine with a starter motor..  got a chevy flywheel.. not a flexplate...  this is just for cranking compression testing.????/ not running..

be sure that the engine has the dist installed   and oil and filter... prime the pump and motor with a priming shaft...    harbor freight has them on sale for like 12 bucks.. this way you wont damage the rod, main and cam bearings while cranking...  

I ran the comp test with the exception of the flywheel. I used the flexplate.   Results came in around 150-160.
 
The more thought I give it, I feel the 305 58cc heads have to go.  I have the option of running a GMC471 4-5 pound boost blower.
   I have a set of #882 76cc smog heads.  The static compression calculator I used says the 76cc heads should bring me down to apprx 8.3:1 C/R.

If cash weren't an issue right now I'd opted for a set of aftermart aluminum heads.

This may be too much to ask, but what would be a good compromise head cc volume for a street engine whether I was using the 471 blower or just  good dual plane manifold w/600 CFM.       The cam is 212/218 @ .050 with 114 LSA.  

The 58cc heads on a dish top piston only gives you a compression ratio of around 8.5:1 I would stick with the heads you have either way.  

If you're gonna use a blower, the lower compression ratio between 8.0 and 8.5:1 would allow you you to run a ton more boost into the engine, making for more power.  

I can't go too crazy with boost cause I only have stock cast pistons  

I have a 350 engine in my truck built with flat tops and 305 heads w/1.94 valves installed in place of the 1.84's with a r.v. cam. It's a screamer and has been in the truck since 1995,driven daily(for the naysayers who say it won't hold together)the only thing I have had to replace is a water pump and I replaced the timing set at the same time at about 90,000 miles for my own peice of mind while I was that far into it. As far as the blower,you're on your own on that.  

Is Hi-Test necessary or can you still use 87 octane?