After some quick searching I still have a couple questions before I drop some money.

While searching I saw one person say that these heads will not work on a 305 block. I personally can't see why not but now my confidence is shaken. So will they work? I'm just looking for a moderate increase in power. The ability to transfer to a future 350 is a big plus. I'll probably have a mild port job done. The heads are off of a crate engine with 5000km, look brand new.

My compression would be somewhere around 9:1 with these 64cc heads correct? or is my math bad?

here's my gameplan:

L69 305
L98 heads
comp cams XE268H
edelbrock 600cfm carb
edelbrock aluminum intake

car is '84 Z28
700R, 3.73 gears

any comments, concerns, 2 bit opinions?

Thanks

 

to clarify these are the cast iron L98 heads. casting # 14101083

I'm on a budget of around 400 CAN for the heads. I can get these L98 heads for next to nothing, have them decked and ported, new valve springs and rockers for right around 400.

I have been looking for vortec heads but I can't seem to find any L31 heads around my area. Used vortecs and machining costs would put me over my budget anyway.

another option is a set of 041X heads, 64cc chambers, 1.94/1.6 valves, rebuilt with GM dual springs and retainers. fits my budget at 400.

a third option is a set of ported 305 heads. not sure of the casting # but the guy says they're 58cc chamber. rebuilt with 1.94 in valves. these heads have been sitting for some time and now have surface rust but I can get them for 200.

Thanks for any input.. I can't get my head(s) on straight

 

the problem with the 350 heads is the much smaller bore of the 305. the valves are very close to the cylinder wall(although I'm not certain, they might make contact , don't know). someone else who has more info may pop in hopefully. the ported 305 heads will keep a good CR and would also swap to a 350. I believe a 416 casting is a favorite. hope this helps

 

They will fit fine, but your compression will likely be closer to 8.5:1 with stock pistons.

 

like the man said, the heads are bigger and you are going to have crappy compression unless you want to use a supercharger.
you cant mill the heads to increase the compression because you want to use them on a 350 later. if you were going to stick with the 305 that would be different, then you could play with them and forget it. also milling might put them to close to the piston. im not sure but i think the piston hitting the valves might be a bad thing when running. lol
as for 305 heads, what are there numbers. the stock swirl ports will not work well - and believe me i looked into it. since you will also need a cam the swirl ports will not give you enough gas, not get rid of enough exhaust and will crap out well before the cam will let you.
if you go with 601 heads, pre 86 - then they are 53cc - will give you 10:1 or so, but you will need to pin the studs so they dont pop out. same for any heads you get - screw them in or pin the studs. you are going to need heavy duty springs and think about rockers. the 601 will take 1.6 for intake but only 1.5 for exhaust, as the exhaust side is already at .510 - and a nice cam - say a zz4 - will top them out at .530 but the intake need help. also you might have to drill the 4 center bolts for the intake to change them from 72 degrees to 90.
im not sure about the other stock 305 heads but there are a few numbers out there.
you can get a rebuilt set of stock 305 heads for about 120.00 per head.
dont forget the smog problems. dont know where you are but heads have different pass through for different intakes.
good lcuk.

 

thanks for the help guys

well I finally made up my mind. It's a good thing I held out for as long as I did. I found a set of World S/R 305 heads from a fellow canadian thirdgener for a very reasonable price.

they're ported and polished, gasket-matched, have comp cams 986 springs, manley valves, and ARP screw in rocker studs. I'm no expert but I'm sure they'll flow a hell of a lot better than any of my other options

new question: what should I do for rockers?

thanks again guys

 

Comp Magnum or Pro Magnum. 1.5:1 would be fine.

You might want to check the chambers of those heads. Mine turned out to be 64cc.

 

I won't be able to cc the chamber until I get them in the mail but I can see 58 stamped into the head from the pics.

the heads are from a TPI setup so I will need a post '86 style intake to run my carb correct? anything special for valve covers?

you can run roller rockers in a non-roller block right? I didn't think that they were related. Will I gain anything from 1.6 rockers?

 

It was cast into mine, and they cc'd at 64.

Unless it was an '85, '86, or Vette TPI.

If they are untouched, you can use perimeter bolt valve covers. In order to use center bolt covers, you have to grind down the perimeter bolt hole bosses. If the previous owner used center bolt covers, you'll have to as well.

I found the '87 LB9 valve covers I had wouldn't fit between the World's gasket rails. Apparently they used an early 90's truck head to get their casting dimensions, and the factory didn't control dimensions that closely. I already had the heads installed on the engine when I discovered this, so I couldn't grind away the inner gasket rail (without removing the heads). And, I had already ground down the perimeter bolt bosses, so I couldn't go back to perimeter bolt covers. I bought a set of Spectre center bolt covers, and they're fine.

They aren't related. The only issue is valve cover baffle clearance, and either of those Comp rockers will clear just fine. The fatter aluminum roller rockers will cause problems.

 

Thanks for the quick response

Did the original owner of the heads port the chambers to add cc's? None of the World S/R heads should have 64cc (from factory). From 58cc the next size was 67cc I think.

Would tall valve covers clear aluminum roller rockers? I can pick up a set of 1.6 aluminum roller rockers for cheap..