Ok so I have an 88 Iroc with tpi and with what I was told to be a 350 under the hood, I know it's not the orginal motor because the guy I got it from said that he had to replace the motor and he got a 350 out of a z71... Well I popped the oil cap off and looked at the heads and discovered that they where 187 heads which to my knowledge or 305 tbi heads so I don't know if this is a 350 or not.... Well anyways I have a chance to get a set of 305 heads casting number 081 that have been resurfaced and cleaned. From what I have read heard you can put these heads on a 350 or 305 since I don't really know what I have, so my question is it even worth the trouble of putting these heads on over the 187 that's on it

 

Anybody??????!

 

081 heads are good heads for a 305. They are also good heads for a 350, but will raise the compression about 1 point over stock 193 heads. They are basically the same head as the 083 heads from the 350 TPI, but 58cc vs 64 cc.

 

See thats the thing I really dont know If I have a 350 or 305, because he said it was a 350 but it has 305 tbi heads on it, what is the pro or cons of the compression raising on the engine?

 

the 187 head is a 305 TBI swirlport head designed for fuel mileage and towing.
The 305 heads also have smaller valves than 350 heads which will dig into the performance potential. The ports are the same, but the valves and chambers are smaller.

First I would look at your engine block to determine 305 or 350.
It will have 5.0 or 5.7 stamped in large letters on the driver-side flange where the block bolts to the transmission. It's just a few inches below your distributor and oil pressure sender. Look from the top of the engine.

A set of regular 305 heads that are ported and have larger valves will improve power on a 305, - enough to be worth the swap.
Simply switching from swirlport heads to regular heads with no other improvements made is not likely to be worth the trouble, especially if everything is running well as is.