hey guys i heard about that guy runnin 14.2 on his lo3 with just edelbrock 2.02/1.60 heads and an intake. i thought that the 2.02 heads were to much for the 305 and i also thought the 64cc chamber would lower your compression to much. what do u guys think? should i get 2.02 heads,lt1 cam, intake, and alot of suspenson mods. i think i should be mid 13's

 

They're 60cc, only 2cc more than stock and he was running the stock cam so the valve hitting the cylinder wall wasn't an issue. He now put on a Holley TBI intake, 670 cfm TBI, LT1 cam, and a D44 rear with 4.11 gears and a spool. NJ Speeders gonna run in 3 weeks with the new combo

 

I took this straight from Edelbrock.com

 

you can disregard what they say. when we installe dthe heads on my car i took out the trusty valve spring compressor and ran tham all the way into teh hole, didn't touch anything. i ran it down to where the spring bound up too, my cam will never come anywhere near that.
the extra 2cc is a drop from your stock rating of 9.2 : 1 to abotu 8.95:1, this is nto significant and can be more than made up for by the fact that you can run more ignition timign because of teh aluminum heads and the sligth drop in compression. most of the iron head guys can run about 4-6 degrees of timing, i was runnign about 10 withthe stock cam.

later
tim

 

i never understood that. the 2.02/1.6 valves should clear any engine larger than the 267. my reasoning is because the 305 has a 3.736 inch bore. the 2.02+1.6 is 3.62. allow a couple thousandths of an inch for space between the valves, and they should fit.

possibly the heads flow too much air for the smaller bores? that's what has me wondering because they don't recommend them for small engines.

 

don't forget the valves are at a 23 degree angle. They aren't parallel to the cylinder bore.

 

I think it just causes some serious valve shrouding. Like the math that robertg did, that's only ~.1" of total clearance and only .050" on each side between each valve and cylinder wall.

Tas brought up a good point about the angle, but a .500" lift cam would only move that valve a total of ~.1" from the wall, and only at full lift. And full lift only happens once. It'll really kill your low-mid range torque because that valve goes twice thru every lift that's below max lift. That's where all the velocity is that you need to build torque, is in velocity to promote swirl, etc.

But after all is said and done, even the math that was done earlier doesn't leave any room for the valves to clear each other. Especially since they (like Tas said) are coming at 23* angles at each other. Unless there's no overlap at all.

Yea, NJ proved that they'll clear, but does that mean that the cyinder bores aren't hindering flow?.... No.

AJ

 

NJ SPEEDER, how much lift do you think you could run with these heads?Edelbrock's cam head package has a flat tappet cam, are the valve springs good enough for a roller cam?What did you use with your head swap(gaskets, push rods) and how much $$$.Can you use stock head bolts with aluminum heads?Any draw backs to these heads?

 

first off, edelbrocks cam is a piece of junk. don't even look at it.
the heads are set up to take .540 total i think, withthe stock valves. i9 forget and it has been a long time since i have seen the info that came with them.
on a 305 the important side to watch is the intake, that is what relatess teh most to vacuum. .460 is safe, .470 can be done, and .480 is pushing the valve shrouding issue.
as you get into more lift and get the valves closser to the cyl wall the air flow can get screwy, it actually slows down the air moving across half the vavle and accelerates it across the other. inside the cyl the combustion chamber and the cyl interact and cause "tumble and spin" this is the action that actually mixes teh air/fuel together to make it a good charge. when you change the air velocities on even a fraction of the valve area, you mess this action up. it alos restricts the amount of charge the cyl can pull in, since it can only really pull air across abotu half the valve.

later
tim

 

Did you reuse your stock head bolts? Did you have to use a longer pushrod? Do you need special gaskets for aluminum heads?
Thanks Tim.

Maybe I'll just stick with my LT1 cam for now if I do the head swap. If I used 1.6 rockers with it that would put me at .477 lift on the intake side. According to your numbers that would put me inbetween do able and pushing it. What do you think, would that work? How's your beast running with your new cam? Are you going back to 1.5 rockers?

I'm either going to do a head swap this year or a engine swap in a year or two. I figure these heads would work fine on a 350 in the future.

 

stock head bolts and stock puxhrods. everything went right in place like stock. all the brackets for the accesaries bolted right up too.

later
tim