Thread: 305 heads

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I got the 305 home for my Camaro on Saturday. It's out of a 91 Caprice and I am putting a cam, headers, Accel 300+, Weiand 142,and holley carb on it. What I am not sure about are the heads. I know that in the late 80's they changed the heads but I do not know anything about them and have not pulled them to check out? Are they good, bad, strong, week? I am looking for about 350hp / 290 - 300 lbs tork so wondering if the new style heads will work for my set up or do I need to dump them and get a set of world heads ( Do not want to have the Vortec's milled down)???

Thanks

Charles

A blower will make up for a world of sins in other areas. Do a good valve job on the 305 heads with a little wider seats than stock and use 'em.

Thanks,

My son just pulled the cover off the heads and they look good, but when I do the valve job I need to put a set of roller rockers in it.

Thanks,

Charles

Use 1.6 on the exhausts. Check for spring coil bind, retainer to guide/seal clearance, piston to valve clearance. If you were using stamped rockers, you'd also check for rocker to stud binding, but with rollers, you can skip this operation.

Rocker roller tips should start slightly toward the intake manifold at valve closed, sweep across the valve stem and be at the center of the stem at 1/2 valve lift, then continue to sweep toward the exhaust manifold at full lift. If the geometry is wrong, get some pushrod length checkers (adjustable pushrods) from any cam grinder and determine the correct length to give you the characteristics I outlined at the beginning of this paragraph. Then order the correct length pushrods according to the length of your checkers that worked the best.

Thanks,

This is great help!!! The last rebuild and valve job was about 30 yrs ago Been a long time and the mind has forgotten a lot.

Charles

Well I just called and got the price on new wider seats and the valve work that I can not do in house, dam... for the extra 100 I can get new world heads They will mill down a set of vortec heads for $90 (thought sure that would have cost a lot more). If I get a set of vortec heads how much do I need to mill them down to make them work well with my Weiand 142? Also anyone know a cheep place to get a set?? Or could I pick a good set of used ones???

Thanks,

Charles

"new wider seats"

I didn't mean for this to be any big deal, just a little wider than stock when the shop grinds the valves to help carry off some of the extra heat generated by a blower.

"for the extra 100 I can get new world heads"

Please explain what's going on here. Extra 100 over what??

"They will mill down a set of vortec heads for $90"

Please explain what you mean by "mill down".

" If I get a set of vortec heads how much do I need to mill them down to make them work well with my Weiand 142?"

Again, what do you mean here???? If you're talking about cutting the heads to decrease the combustion chamber volume, STOP. You don't understand the basics of supercharging. Purchase this book immediately and read it cover to cover....
http://www.amazon.com/exec/obidos/tg...books&n=507846

"new wider seats"
Sorry, thought you ment to have a little larger seat put in, did not think about having them ground down.

"for the extra 100 I can get new world heads"

I called a couple shops and to get the heads cleaned and new guides, seats and valves was $614 maybe a little more. I was looking at a set of World heads for about $745.

"They will mill down a set of vortec heads for $90"

Everyone I have seen using the vortec heads on the 305 have them milled down to decrease the combustion chamber volume. I thought maybe that you had to mill the vortec heads down to get them to be the same volume / fit as stock heads.

" If I get a set of vortec heads how much do I need to mill them down to make them work well with my Weiand 142?"

From your other posts I would think that I would leave the vortec heads alone with the increase in the combustion chamber volume to help them run cooler.


I did find that I can get a set of used vortec heads for 125 each if the Vortec heads would work better for me.

Thanks for the book tip, never had a supercharger just my turbo on my truck.

Thanks,

Charles

"I did find that I can get a set of used vortec heads for 125 each if the Vortec heads would work better for me."

Sounds like a good deal to me. Read about them here and make sure what you're getting. Pay attention to the limit on valve lift with the stock Vortecs......
http://www.sallee-chevrolet.com/Cyli...ds/Vortec.html

Thanks,

Got my book on order. Any other book I can get to help out to learn about the heads??? Just not sure about what you mean about pay attention to the limit on valve lift with the stock Vortecs......??? I think that you mean to watch out doing a valve job that I do not grind the valves / seats to much and get to much lift???

Been way to many years..

Charles

Just don't choose a cam that has valve lift over the limit of the heads unless you do some work to them with different springs and clearancing on the retainer to seal clearance.
http://chevyhiperformance.com/howto/97458/

Sallee Chevrolet adds this....
The Sallee Chevrolet solution is to use Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining.

If you'll click on the Sallee Chevrolet link that I gave you and read all the way to the bottom of the article, you'll learn what I'm saying.

Thanks,

I checked back on the used vortec heads and they could not tell me what they came out of. Looks like I will keep what I got unless I find a good deal on something better.

Charles