55.2-59 Engine rebuild. Question on heads

[Phungki]

So I got my motor. After tearing into it, I found out it had heads off of a 78’ 305. Not terrible but not great either. They need rebuilt as well so I figured I would look into a more desirable set of heads. Here is where my question comes in. From what I’ve read on this site and others is that getting headers that fit is kind of a bear. I guess the “rams horn” style is the way to go? So I was wondering since I’m getting different heads anyway should I be looking for ones with straight plugs or angled? I appreciate any and all advice. Here is a pick of the engine coming out and a pick of my finished front end it’s going into. Just because we all like those pictures
Thank you
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[Rickysnickers]

Shameless plug, how about these? http://67-72chevytrucks.com/vboard/s...d.php?t=794278.

[Phungki]

Originally Posted by Rickysnickers

Shameless plug, how about these? http://67-72chevytrucks.com/vboard/s...d.php?t=794278.

Thx but I won’t be spending that kind of money on heads. You didn’t answer my question tho. Which had to do with straight plugs or angled is easiest for headers. Finding headers in my price range isn’t an issue

[mr48chev]

Factory angle plug heads only came over the parts counter and never on a production vehicle as far as I know. Truthfully unless you run domed pistons with 11.5 or higher compression ratio they are a waste anyhow as they are designed to work with domed pistons and not have a flame travel groove in the piston dome.

Now days you should be able to buy a set of decent cast iron heads from Summit or Jegs with valves and springs installed for what a set of "good" used heads and a fresh valve job costs.

Either way you need to study up on it a bit and find heads that will do what you need them to but not be more than you need with a performance stage that your engine doesn't need.

I kind of had my buddy's valve grinder sold out from under me yesterday when I was too late asking about it. I had done a number of heads with it over the past 25 years.

[svr]

Hears a list of casting numbers and what they are. Might help confusion or add to it.
http://outintheshop.com/faq/casting/heads.html

[Phungki]

Yeah not confused on heads in general. My only real question is since I’m getting different ones, which ones make it easier for fitting headers?
I will probably be getting a set from summit unless I find a set of 041 or 186 with a price I can’t pass up.
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[1project2many]

Are you sure that's not a 305 engine? Monte Carlo's were never equipped with a 5.7 after '77. The original 305 heads will have 58 cc chambers and 1.72/1.50 valves. Switching to a larger chamber will give up compression. There is additional concern of older 5.7 heads having the valve centers farther apart which, combined with 1.94" or 2.02" valves can cause conflict with cylinder block.

1980+ 305 heads generally have 1.84/1.50 valves for better flow. Because the valve centers are closer together you can use 1.94" valves with a mild cam. Or you can use a head with wider centers and pay to have the valve center moved. But you might not gain much. TPI aluminum L98 heads are 58cc and have 1.94/1.50 valves while the 305 version comes with 1.84" intake. Aluminum headfs can allow more advance without the detonation.

My truck uses a set of cheapie headers that I removed from a '74 K1500 in the '90s. The actually fit well. I welded the flanges up then had them machined flat, and I cut the upper flange into three sections to allow for expansion. I have doughnuts at the bottom to allow engine flex. The headers have been installed since '96. I have 1985 305 heads using straight plugs on a 302 bottom end. Some of the plugs are a little tight and require me to install the spark plug socket on the plug then a wrench on the socket. No big deal.

[Phungki]

It’s not the original engine from that car. Looked up the casting number and confirmed it was a 350.

[1project2many]

Originally Posted by Phungki

It’s not the original engine from that car. Looked up the casting number and confirmed it was a 350.

Well that's good news. But youch! 305 heads on a 350 can cause pretty severe detonation issues. It raises compression significantly and the sharp edges of the chambers can get hot enough to be a trigger point.

Modern head designs for street vehicles don't require angled plugs to get best flow. Go with straight.

Be warned that if you get a Vortec head the centerline of the exhaust ports is not in line with the centerline of the bolt holes. You may have to "walk" the holes closer to the top of the header.

[Phungki]

Originally Posted by 1project2many

Well that's good news. But youch! 305 heads on a 350 can cause pretty severe detonation issues. It raises compression significantly and the sharp edges of the chambers can get hot enough to be a trigger point.

Modern head designs for street vehicles don't require angled plugs to get best flow. Go with straight.

Be warned that if you get a Vortec head the centerline of the exhaust ports is not in line with the centerline of the bolt holes. You may have to "walk" the holes closer to the top of the header.

From what I have read there really isn’t a significant difference in performance between straight or angled. I was just wondering about header fitment. If either one gave me more options.
I’ve read vortec is a better head but I believe I would also have to change my intake if I got those. I don’t want to do that. The one it has is fine. I’m not trying to squeeze every horse out of this thing anyway. But to get these heads redone is only about $175 away from a new set at summit so I figured I’d go that route
And end up better off
Thank you for the responses. I appreciate the input from ppl who have “been there done that”

[1project2many]

But to get these heads redone is only about $175 away from a new set at summit so I figured I’d go that route
And end up better off

Agreed. 305 heads on a 350 are not a good choice. I think most of the answers spoke of cylinder head performance because folks pick the heads they want then try to get headers to fit. I do not believe headers designed for our trucks would be built with angled plugs in mind. If you are going with ram's horns you'll almost definitely want to use straight plug heads.

[Phungki]

Originally Posted by 1project2many

Agreed. 305 heads on a 350 are not a good choice. I think most of the answers spoke of cylinder head performance because folks pick the heads they want then try to get headers to fit. I do not believe headers designed for our trucks would be built with angled plugs in mind. If you are going with ram's horns you'll almost definitely want to use straight plug heads.

That’s pretty much the answer I was looking for.
Thank you