Thread: head identification

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last year i purchased a 79 caballero with a 350, the previous owner pulled the engine from a 86 chevy truck, last month I pulled engine and transmission while doing a transmission swap and figured i would put new gaskets on the engine while it was out. also figured i would add some HP, after tearing apart the engine I identified it had 305 heads on it with casting number 14022601, I visited many databases with conflicting info, some say they are 53cc and some say 58cc, also some say valves are 1.84/1.50 and some say 1.72/1.50, im not sure how to tell which valves are in the head or what cc they are, any ideas???

Originally Posted by cabellerosteve

I'm not sure how to tell which valves are in the head or what cc they are, any ideas???

Welcome to CHR!

If you have the engine apart, why not measure the valves and check the cc volume? A piece of plexiglass and some Vaseline to seal, plus a container marked in cc's tells the tale. With your story, knowing that the PO pulled the engine from an '86 truck I'd be concerned that it's a 305 and not a 350. I suggest you check the casting number on the back of the block, just below the intake and the numbers stamped on the block in front of the passenger side head, just in front of the sealing surface to see what you have.

Or lay a tape measure across the intake valve and measure the head of it. if it's less than 1 & 3/4"( 1.72") or closer to 2" (1.84") you'll have an answer.

Welcome to CHR:

As you already determined, these heads were used on 305 engines and have 53cc chambers. They were also used on the ill-fated 267 engine. Here’s the difference - The 267 used 1.72/1.5 valves, the 305 used 1.84/1.5 valves. I share Roger’s suspicions that you have a 305 engine that the PO may have thought was a 350. Now that you have the heads off, simply measure the bore. Stock bore size:
267: 3.500”
305: 3.736”
350: 4.000”
Find the casting number for the block and then we can determine what the engine was when it left the factory. Also helpful is the number on the block at the front left (passenger side).

Since you have the engine out and you’re interested in adding a bit of zip to your ride, you may want to consider some options. If the engine is a 305, I’d not put a ton of money into it. If you have a 350 from a 1986 truck it’s not a roller motor. Either case, unless you want to work what you have, you may be better off starting with a crate motor. To put a 350 back together with decent heads can quickly eat up a couple grand. A roller long-block crate engine can be had for as little as $2,200 for a 250 horse bullet proof GM truck four-bolt with a warranty. You can go a little crazy and for about $5k have a fire breathing 400+ HP, 383 stroker motor and there’s some options in between.

So, get the block numbers and then you can determine what you have and how much you want to spend.

Again, welcome to CHR!
Glenn

already checked the block numbers and determined it is in fact a 350 block casting number 10054727, I believe they put 305

heads on to increase compression, all sources were conflicting as to if they were 53cc or 58cc, haven't pulled the heads off yet but I guess I will this weekend, was looking into replacing rockers with 1.6 and was concerned if that would require race fuel as I have read some posts indicating that to be the case with 53cc chambers with this set up

engine runs great, not looking to dump thousands into a car that wont reflect it in resale value, but I don't mind spending time, and a hundred or two, just don't want to change things to find out later I have to run high octane instead of regular gas, maybe this is not an issue im not sure? I was planning on porting the heads myself and replacing the valve seals, new gasket set with head bolts and 1.6 rocker upgrade, most of my work is in the trans swap going from th350 to 700r4, and 2:56 ring and pinion to 3:73 posi as the gearing change should bring the car to life. my other concern was the torque converter as I have heard the stall should be matched to the cam, and with no idea what cam is in the engine im not quite sure where to go with that. the engine has a dual plane weiland intake and edelbrock 650 carb, timing cover looks to be original so could be stock cam, is there a way to tell? and by the way thanks for all the info you guys are great!