Another 302 Head Question

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Check the 302's to be sure they are not cracked, usually visible between valves. If all is well, match roof and middle divider of intake only, sides and roof of exhaust only. Smooth transition in bowl, both intake and exhaust. Intake is suction, Exhaust is under pressure. Get a good valve job. Your engine should start within one revolution. Mill the heads .020 block side, .019 intake side. Use Felpro Head Gaskets and do not use steel shim intake gaskets. Don't swap gears. For your purpose they are perfect.
 
66fs said:
Check the 302's to be sure they are not cracked, usually visible between valves. If all is well, match roof and middle divider of intake only, sides and roof of exhaust only. Smooth transition in bowl, both intake and exhaust. Intake is suction, Exhaust is under pressure. Get a good valve job. Your engine should start within one revolution. Mill the heads .020 block side, .019 intake side. Use Felpro Head Gaskets and do not use steel shim intake gaskets. Don't swap gears. For your purpose they are perfect.
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Okay! Thanks for the advice!
 
AJ/FormS said:
Details in post #25
Ow on the super tall tires with just 3.54s and
Ow on the 1600TC
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Lol I hear ya now. Those numbers are really an eye opener! Thanks a lot!
Now I'm in a predicament, that 2800 stall sounds real attractive but I do plan on occasionally towing later on; possibly for over 4 hours at highway speeds. How will the 2800 stall effect driveability? Even unloaded at highway speeds (2500rpm), it would have me revving much higher?
The 302's are still going to go on, I appreciate your opinion and understand completely, it's just something to occupy my idle time during school breaks while i'm home, like Christmas
 
JJH said:
Lol I hear ya now. Those numbers are really an eye opener! Thanks a lot!
Now I'm in a predicament, that 2800 stall sounds real attractive but I do plan on occasionally towing later on; possibly for over 4 hours at highway speeds. How will the 2800 stall effect driveability? Even unloaded at highway speeds (2500rpm), it would have me revving much higher?
The 302's are still going to go on, I appreciate your opinion and understand completely, it's just something to occupy my idle time during school breaks while i'm home, like Christmas
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No sweat,lol. My 2800 is circa 1980, with old technology. I actually worked at the place they were built and saw how the built it; it was real low tech. And I drove the crap out of it for many years and several cars with no transcooler.
I have no personal experience with the modern stuff, but there are plenty of guys on FABO that will chime in.
If you look at that graph again, you can see the torque curve is pretty good, so YOU might not need a 2800. I just recommend it cuz it's so darn much fun.
At 2400 for instance, that curve is still putting out 285ftlbs and 130hp. Which is still way better than 80,lol. If you keep the 3.54s it looks like this;
285x2.45x3.54x.8=1977 ftlbs to the road, which will still spin two typical width tires. And your cruising speed will be 65=2585 @zero slip, so I don't see a problem with a 2400, and a small cooler, but I wouldn't go any less.
With your cam and a bump in compression, your LA might be on par with this Magnum.
Those 30s you mentioned, wouldn't be other than a street tire or perhaps an LT type.....would they?
 
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They are Load E tires, but they are also a winter tread.... got a real good deal on the size rears I wanted lol. They are soft so I know the truck will suffer more trying to spin em. And as for transcooler, i've got an aluminum 3 core rad with the trans cooler; should that suffice?
 
And if you don't mind, could you clarify where the 24 came from when you did 24/30=0.8 please? I understand everything you've said besides that 24
 
JJH said:
And if you don't mind, could you clarify where the 24 came from when you did 24/30=0.8 please? I understand everything you've said besides that 24
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That's a correction factor to a 1 ft radius so I can accurately say "X" amount of ftlbs to the road instead of into the rear axles; which is way less meaningful.
Example
285 crank ftlbs x2.45 trans gearx3.54 rear gear maths out to 2472ftlbs into the rear axles. If your tires were a 24 diameter and so a 1 ft radius, then to the road would also be 2472 because the correction factor is 24/24=1
If you had a 5ft tire the correction factor would be 24/60=.4 so then, to the road would be 2472x.4=989 and your teener is not even gonna squawk that,lol.
But your 30s are 24/30=.8 so you get 1978 to the road, enough to break the loose.
Doing it this way allows an apples to apples comparison when comparing performance changes due to tire height changes.
I know, clear as mud
 
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Thanks! That makes perfect sense. Being metric, I don't pick up on 12 = 1' and all that very often. Lol
 
I'm Canadian too, but since I became a wrench before the government mandated and enforced the Metric crap system, and made me buy new tools, and I now have to measure the bolt-heads before every trip to the toolbox, I'm bi-lingual.
 
AJ/FormS said:
I'm Canadian too, but since I became a wrench before the government mandated and enforced the Metric crap system, and made me buy new tools, and I now have to measure the bolt-heads before every trip to the toolbox, I'm bi-lingual.
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Lol it's too bad Canada jumped the gun on switching. Being in college for MEng, I have to be proficient in both as well..... that's gonna take some work :BangHead:
 
What year was that? Lets see, maybe 76/77/78-ish. So I've had over 40 years of wrenching pleasure, on he dual-systems. But very soon now, there won't be any non-metric stuff left,besides Harleys, and so the next generation won't have anything to complain about.
I wish you all the best in your career choice. If things had been different in 1972, I would have chosen that path too.
 
AJ/FormS said:
What year was that? Lets see, maybe 76/77/78-ish. So I've had over 40 years of wrenching pleasure, on he dual-systems. But very soon now, there won't be any non-metric stuff left,besides Harleys, and so the next generation won't have anything to complain about.
I wish you all the best in your career choice. If things had been different in 1972, I would have chosen that path too.
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Thank you very much! So far I'm enjoying it. I wanted a career that I could work with my hands but still have the time and resources to feed my hobby lol. As we both know, vehicles aren't the cheapest to play with
 
Called the engine shop today.... one of the 302's is cracked between the exhaust and intake valve. He is unsure; there is a possibility that they have a core sitting out back. He's going to check for me.

Anyway, if he doesn't, what should be my plan of attack? Pull the original heads, have them milled, can hardened exhaust seats be installed?, and a lil port and match work?
Or should I pick up some aluminum heads?
I personally think aluminum heads are a waste. My intake is 318 sized, my cam is small and I need torque. Larger ports and valves on aluminum heads will slow air velocity; therefore reducing low end torque and response. If you think differently, tell me. Still going to upgrade the converter either way.
Cam is all in by 4500rpm anyway lol. Intake range does not extend much further
 
JJH said:
I personally think aluminum heads are a waste.
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on your combo probably, most likely, I wanna agree 100%, but have to leave a lil room for...........How much you gotta spend on getting something else to bolt on.
Thing is aluminum heads suck a lotta heat out of the chambers; and if you don't up the cylinder pressure, then you can lose a very significant amount of power at normal rpms and loads, just when/where you need it the most....... in a streeter with street friendly gears and TCs.
And a street teener just can't afford to lose that grunt. If you are staying factory stroke, it's really hard to get the pressure up high enough to take advantage of aluminum heads.
And it would be far more cost effective to just start with more swept area.For stock engines,per cylinder,the 318 is ~652cc, the 340 is ~700, and the 360 is ~750ish. Say you put 78CC total chamber volume on each of these; The Scrs come to; 9.36, 9.97, and 10.6, none of which are really adequate for aluminum, but the 360 is closest by a very significant margin, and so, loses less pressure when up-camming..
 
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JJH said:
Called the engine shop today.... one of the 302's is cracked between the exhaust and intake valve. He is unsure; there is a possibility that they have a core sitting out back. He's going to check for me.

Anyway, if he doesn't, what should be my plan of attack? Pull the original heads, have them milled, can hardened exhaust seats be installed?, and a lil port and match work?
Or should I pick up some aluminum heads?
I personally think aluminum heads are a waste. My intake is 318 sized, my cam is small and I need torque. Larger ports and valves on aluminum heads will slow air velocity; therefore reducing low end torque and response. If you think differently, tell me. Still going to upgrade the converter either way.
Cam is all in by 4500rpm anyway lol. Intake range does not extend much further
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You can also use the 66 and 67 273/318 heads. #178,234, and 920 castings. All are 273/318 port and closed chamber with 1.78/1.50 valves They may be a little easier to find than the #302's.
 
I would look around, but most old vehicles are scrapped here. Not many survivors and the ones that do survive, are in use lol. I have yet to see a 273 around, and canada kept the Poly till 67 so that rules out 318s sadly lol. Are hardened exhaust seats something that can be installed? How costly?
 
JJH said:
I would look around, but most old vehicles are scrapped here. Not many survivors and the ones that do survive, are in use lol. I have yet to see a 273 around, and canada kept the Poly till 67 so that rules out 318s sadly lol. Are hardened exhaust seats something that can be installed? How costly?
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Yes, hardened seats can be installed. Some just replace the valves with stainless and call it good. I talked with my machinist when I built my 273 and we didn't replace the seats or stainless valves. I only put a couple thousand miles a year on the car at the most. It will be a decades before there is an issue.
 
I've heard it said that Mopar actually started installing hardened seats in 1970, or 69.
There have been many comments on here as to the cracking on 302s being a non-issue
I cannot comment as to the truth of either of those comments.
 
I would run what you have, 675"s, Mill and prep them the same as I said above. Get Stainless steel exhaust valves and have a good valve job done. As I understand it, typical exhaust valve material is Stellite, sp. The cast iron from the seat sticks to the valve and then acts as a hole cutter and drills the valve into the seat and down. The cast Iron does not stick to the stainless steel and there is little erosion. Also the metallurgy of Mopar cast iron is better than lesser brands. I would not take the chance on installing exhaust valve seats unless there was a problem. You can cut into a water jacket or if not machined properly the seat can come loose.
 
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