302 head progress and questions

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jrc4y4

jrc4y4

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Picked up some 302 heads. Prior owner had 1.88/1.60 valves put in. Pulled off running car and picked up for what I felt was fair. I’m learning as I go on this and just wanting to make sure I’m doing the right things. Pics of before and after (sorry limited pics). Guy said he ran them on 360 and running 8.20s in a valiant.

I’ve ported the intake side of the heads, focusing on the roof and walls, and just cleaning up the floor based off of what I’ve learned. Now I’m looking into doing the exhaust ports and then deshrouding on the chamber side based off of things from MoparOfficial (who loves these heads by the way ) and advice from others. So far I found a valve that needs replaced and a cracked guide. After my port work I plan to take it to the machinist to have em hot tanked, looked over, and the guide and valve replaced. Wasn’t planning on doing a 3-5 angle valve job unless I need to.

Car: 72 Scamp, 318, .030 over silvolite pistons, 470 lift comp cam, 600 eddy intake and performer intake (I plan to port the intake while I’m in there), 904 with 2800 stall, 8.25 with 3.92 sure grip. Putting on headman headers while I’m in there too.

Honestly it was supposed to be a valve seal job but we found issues in my factory heads and these 302 heads came up so I went that route due to having bigger valves. Have gone way over budget (a term I use to keep the Mrs happy lol). I know I should run head X, get a 340, turbo my 318, etc, but it’s a street cruiser that I wouldn’t mind dipping into the 13s while not breaking the bank too much further going from just valve seals to heads and headers lol.

Just wanted to see if there was any other things I’m missing on dealing with these heads that I’m overlooking. Thinking clean up chamber some, exhaust ports, then have the valve and guide. Anything I’m missing? Thanks for any input!

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Get some gaskets 1st.
Make sure they in place/ aligned properly..taped etc.. or held by a firm hand...then use a paint pen to trace..
That's what you grind to..leaving some red/paint behind in a even line for a every side of each port...then use a file to finish with.
No novice without challenge will ever land a gasket match accurately...so that's what I say you do.
I'll put part 3 up soon. Was looking for more interest still..
 
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MOPAROFFICIAL said:
Get some gaskets 1st.
Make sure they in place/ aligned properly..taped etc.. or gold by a firm hand...then use a paint pen to trace..
That's what you grind to..leaving some red/paint behind in a even line for a every side of each port...then use a file to finish with.
No novice without challenge will ever land a gasket match accurately...so that's what I say you do.
I'll put part 3 up soon. Was looking for more interest still..
Click to expand...

Cool I got my gaskets and a paint pen so I’ll work on that.

Assuming the valves are fine, would I be wrong to not have a valve job done when they’re checked over?

Look forward to part 3. Will it have the exhaust ports? I don’t want to get into water lol.
 
jrc4y4 said:
Cool I got my gaskets and a paint pen so I’ll work on that.

Assuming the valves are fine, would I be wrong to not have a valve job done when they’re checked over?

Look forward to part 3. Will it have the exhaust ports? I don’t want to get into water lol.
Click to expand...

A valve job is far more important than the grinding you are doing. I’m not trying to discourage your porting, but not doing a quality valve job is the worst decision you can make. All porting starts with the valve job.
 
Rat Bastid said:
A valve job is far more important than the grinding you are doing. I’m not trying to discourage your porting, but not doing a quality valve job is the worst decision you can make. All porting starts with the valve job.
Click to expand...

Alright so prior guy did 1.88/1.60 valves but didn’t cut them down into 3 or 5 angles, just stock cut but bigger than factory 1.78/1.50. You’d do a 3 angle on it still? Just want to make sure I’m following.
 
“In theory”, a valve job would have been done(seats ground or machined) to facilitate the use of the bigger valves.

I’ll go against the grain here and say that unless that previous work was done very poorly(very possible), and/or there are noticeable issues with how the valves are sealing, remachining the seats to “race quality” standards........will not have much impact on the cars ET with the type of combo you’re working with(low hp/ci).

But, someone needs to assess how serviceable the condition of the seats and valves currently are before making that call.
 
jrc4y4 said:
Alright so prior guy did 1.88/1.60 valves but didn’t cut them down into 3 or 5 angles, just stock cut but bigger than factory 1.78/1.50. You’d do a 3 angle on it still? Just want to make sure I’m following.
Click to expand...


No to be a smart azz but the 3-5 angles is on the head valve seat. The valves will have a 45 degree angles with possibly a 30 degree towards the valve stem. You may need blueing on the valve seats and bifocals to see all the angles
 
pittsburghracer said:
No to be a smart azz but the 3-5 angles is on the head valve seat. The valves will have a 45 degree angles with possibly a 30 degree towards the valve stem. You may need blueing on the valve seats and bifocals to see all the angles
Click to expand...

lol all good. Yeah I already pulled the valves and they didn’t have extra angles put on them. I could double check though, but on my old heads I had a 3 angle and saw it clearly. I’m only 32 and still have good eyes with glasses
 
The seats can be done with stones or with a machine like these were done. This was done on a Serdi.

11_14_0.jpgcrop.jpg
 
I agree with the 3-5 valve job being a do first. From what I have heard, biggest gains in intake port are 1. Opening up the bowl under the valve. 2. Smoothing out the short side radius, bigger the radius the better. 3. Opening up the push rod pinch point. And 4. Floors on intake side and roofs on exhaust.

does anyone agree with all this? Opinions?

I would think you would be able to get into high 12’s with this car, but compression ratio will be key.
 
I already pulled the valves
Click to expand...

Clean a few valves seats good with some solvent and like a scotch bright pad...... take a few pics, and let’s see what you have.
You could also wire wheel a few valves and lap them in to see how the contact looks.
 
PRH said:
Clean a few valves seats good with some solvent and like a scotch bright pad...... take a few pics, and let’s see what you have.
You could also wire wheel a few valves and lap them in to see how the contact looks.
Click to expand...

Alright when I get back out to the shop I will try and snap some more pics. Appreciate the info.
 
ch1ll said:
I agree with the 3-5 valve job being a do first. From what I have heard, biggest gains in intake port are 1. Opening up the bowl under the valve. 2. Smoothing out the short side radius, bigger the radius the better. 3. Opening up the push rod pinch point. And 4. Floors on intake side and roofs on exhaust.

does anyone agree with all this? Opinions?

I would think you would be able to get into high 12’s with this car, but compression ratio will be key.
Click to expand...

I’ve been reading and need to know what is meant by short side radius and pushrod pinch point. Sorry this is the first time I’ve touched heads. When I had my engine rebuilt 15 years ago I had the long block done.
 
A word of advice if you’ve never ported any heads.

Get a junk head to practice on before going all in on the heads you’re planning to use.
 
PRH said:
A word of advice if you’ve never ported any heads.

Get a junk head to practice on before going all in on the heads you’re planning to use.
Click to expand...

what if it’s too late (maniacal laugh while holding drill with carbide bits)? I appreciate it. I’m getting some supervision from some more experienced guys
 
jrc4y4 said:
Cool I got my gaskets and a paint pen so I’ll work on that.

Assuming the valves are fine, would I be wrong to not have a valve job done when they’re checked over?

Look forward to part 3. Will it have the exhaust ports? I don’t want to get into water lol.
Click to expand...
Yes.
Again, try and get the window opened to the port runner shape, its oval and smaller in the pics. Work the guide, don't leave its length humped in the middle when you finish. Leave it ramped like the turn, mimic the floor somewhat, narrow it. Get it to half of it's as cast size and out of the way. Shorten the guide too, 3/8 at the hole, leave the material beyond the valve guide hole on the bowl and profile that to a peak that quickly blends to the bowl. Move the straight wall over some..make the bowl the largest area and not the entire half of the runner leading to it.. push back on the top of the short turn at the straight side aka common wall.... make it look like the other side but slightly higher...and shoot for opening the bowl to 85% and it will make really good power. That's assuming all the chamber work is done...which is no.1
 
MOPAROFFICIAL said:
Yes.
Again, try and get the window opened to the port runner shape, its oval and smaller in the pics. Work the guide, don't leave its length humped in the middle when you finish. Leave it ramped like the turn, mimic the floor somewhat, narrow it. Get it to half of it's as cast size and out of the way. Shorten the guide too, 3/8 at the hole, leave the material beyond the valve guide hole on the bowl and profile that to a peak that quickly blends to the bowl. Move the straight wall over some..make the bowl the largest area and not the entire half of the runner leading to it.. push back on the top of the short turn at the straight side aka common wall.... make it look like the other side but slightly higher...and shoot for opening the bowl to 85% and it will make really good power. That's assuming all the chamber work is done...which is no.1
Click to expand...

sounds way more involved than what I’m looking to do. I’m like 9 hours into these things lol. Ugh.
 
jrc4y4 said:
sounds way more involved than what I’m looking to do. I’m like 9 hours into these things lol. Ugh.
Click to expand...
Ah okay.:D
Unless you're just an animal and dont mind finger/hand pain and spotty numbness in your arms...you'll need to take your time. Do things in sessions for each feature, port windows, guides, bowls, straight/common walls ,short turns.
:thumbsup:
 
MOPAROFFICIAL said:
Ah okay.:D
Unless you're just an animal and dont mind finger/hand pain and spotty numbness in your arms...you'll need to take your time. Do things in sessions for each feature, port windows, guides, bowls, straight/common walls ,short turns.
:thumbsup:
Click to expand...

I mean I don’t mind the numbness and pain. Just the value of hp vs value of my time lol. That and wanting to get the thing back on the road for car show season!
 
jrc4y4 said:
I mean I don’t mind the numbness and pain. Just the value of hp vs value of my time lol. That and wanting to get the thing back on the road for car show season!
Click to expand...
It'll only be as good as the amount of time you take to do it.
Those are thee most involved casting of cylinder head for the these motors to get in shape to make good power.
Bolt on they are small bump in compression..but take a hit in air flow when compared to the other castings.

Watch the video and compare the as cast with the chamber work and valve job I did.
Both the chamber work and valve job are key to how they turned out to that point.
Your results will vary if you skimp on the detail/valve job.
 
toolmanmike said:
FOR SALE - Dodge 273 Engine 302 Heads
Click to expand...
Those are opened up at the windows, but that's about it. The chambers are std.
You can port all you want and itll only get better above .450 'somewhat' because the ledge below the short side in the chamber.
That aside..
That was good deal too! I remember it on here somewhere for like a grand or something.
 
MOPAROFFICIAL said:
Those are opened up at the windows, but that's about it. The chambers are std.
You can port all you want and itll only get better above .450 'somewhat' because the ledge below the short side in the chamber.
That aside..
That was good deal too! I remember it on here somewhere for like a grand or something.
Click to expand...
Yes. The machine work and porting looks good but like you said porting alone isn't the key. I have a local machine shop that does a lot of circle track heads. The rules don't allow porting but a good valve job and a back cut on the valve sure helps.
 
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