Ok As of right now I have a carb'd Lo3 with a lt1 cam in it, I got a zz3/zz4 cam for twenty bucks along with a set of 95 chevy truck 350 heads which are 1.94, 1.50 valves. They are fresh with brand new valve job and comp-918 springs. I want to run this head on my 305 l03 bottom end, with the zz3 cam and 1.6 rockers. This would make the lift .505 .544, and since it is a nitrous car it would be a perfect split for intake and exhaust lift.....the thing I need to kno is will I have any clearance issues between cylinder and valve or piston and valve...Im not too sure if I will, I plan on running a stock thickness gasket and no milling on the heads. Thanks...

 

'95 truck 350 heads are swirl-port heads, don't use them.

 

Hmm, those heads probably won't be much of an upgrade eh? They're still swirl ports, just bigger chambers.

piston-valve won't be a problem.

You will most likely have issues between retainer and guide on the heads. Have a machine shop measure your heads to tell you the max lift you can take on them, and then tell them you need to run. .544", and to tweak it for that.

 

Why spend money at a machine shop for heads that aren't any better? Get some other heads, then worry about clearances. You'd do better with LB9 heads. Or milled vortecs. Or aftermarket iron 180cc heads with 50cc chambers. Or best of all for a 305, the TrickFlow 175s that are intended for 305s. Edelbrock Etec 170s work okay. But the best thing is to call AAMidwest or LKQ Corp. for a good used Vortec 350. Less money, more performance.

 

they are much bigger valve, and since this is a nitrous car i figured it would help...i was told they were ho heads off a 2500 pickup, and the previous owner had them on his car with 550 lift, im unsure buying a motor or another set of heads is out of the question.

 

Going from a 1.84" valve to a 1.94" valve is no help when the 1.84" valves already outflowed the tiny intake ports. At this point, almost any worthwhile option is gonna run you $500, and the best return on investment at that price is a used Vortec 350, from a '96-'98 fullsize halfton chevy/GMC pickup.

 

I agree whole-heartedly with Atilla. He hit the nail on the head.
Valve size isn't as important as yur basic hillbilly thinks it is. The ports on these god-awful swirl port heads are limiting you.

 

I guess ill just spray more at it, the old set-up which was the bone stock-140,000 mile l03 with a lt1 cam and 650 carb, nos powershot, 125hp jets went 12.9X at 111...all through the 5 speed and a 3:23 gear...hoping to hit low 12's or 11's still with the 305..and the raceweight was 3000 pounds with me in it.