360 heads on a 318, I know it has been beat to death...

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POPS6T6

POPS6T6

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I have read all that I can on this subject, and there are quite a few good articles out there, but in the end I am just as confused as I was when I first started reading! I am getting mixed reviews and not sure where to go with this. I have a 318 bored .40 over, Air Gap intake for it, Edelbrock 600 cfm carb and I have a set of 360 heads that I was considering putting on. I took them to the machine shop, and he wants close to $700 to re-surface them, add new valves, guides, springs and all the other machine work on them . I am not sure if they are going to be worth it or not. I am attempting to build this engine on a budget, and I am also not trying to build a "perfect" drag engine, just something with a little punch to it and fun to drive. My fear is that I am going to continually put more money into it trying to get it to run right. One of major concerns is that the cam I got is way to big for it. (that is what I get for listening to a "Chevy" guy!) I have a Crane Cam 467/494 (summit part # crn-693802).

Is it possible to get the motor running good with the 360 heads milled down and that cam setup? This is the first motor I have ever built or been involved with building, so when the talk gets technical, I tend to get lost.

Any good simple advice out there?

John
 
What exactly is he doing for $700. It seems to much.
That Crane will work well with a set of those heads pocket ported at most with stock size 360 valves. I really do not see a need for 2.02's on the intake. The cam is still small. (222* - 234* @ .050 and under .500 lift.) According to Crane, that performs in the 2200 - 5200 range right or is that Summits range?

I suggest that if you need to mill the heads, get a ratio of no greater than 9.5-1. Thats enuff for a good performaing engine on pump gas safely.
Theres no need to do more than pocket porting at best. Save the cash for that until later. The port volume is enuff on that engine.
 
dude first thing you need to do is find a new head shop. $700 for machine work is criminal. I did a set of stock 360s with full porting, new springs, new 2.02 intake 1.6 exhaust swirlport valves, and shaving .030 off for $510 out the door.

that cam is alittle weird of a choice for a mild(ish) street motor. A flat tappet is not a common street cam but other than that below 500 lift and under 290 duration should be ok. the cam will be alittle restricted in regards to your engine's flow ability but once you dial it in it will be alrigh (I am a huge supporter of dyno tuning btw).

Oh and depending on the year the heads came from you will need hardened seats (I think its '78 and up they came hardened).
 
I am begining to think this guy (who is reportedly a very good engine builder) is either trying to scam me, or just isn't sure what I want. That was putting it nicely.

If I were to use these heads, what should I ask him to do? And what should I expect to pay?

Basicly looking for a good list of request to get the most for my buck and the best performance for my buck.


Also, the casting # on the heads are : 4027596 which are 1977-1980 66.0-72.5 cc
 
Clean them up and put on the new valve springs. After that, the amount of actual cc's the head has would help me determin what I would need to mill off to get where I wanted to be.
It's been awhile since I had heads milled, but I payed $35 a head for a light cut. (Though my buddy said he'd do .060 for me)
Springs are easy. I used to do them for a nice sandwhich for lunch. But that was a long time ago. LOL. I guess I'd charge $60 for the springs, head milling around here at a good shop is about $100. Pro shops charge more.
 
POPS6T6 said:
Is it possible to get the motor running good with the 360 heads milled down and that cam setup? This is the first motor I have ever built or been involved with building, so when the talk gets technical, I tend to get lost.

Any good simple advice out there?

John
Click to expand...


Yes. My daily driver has a 480lift, 280 dur comp cam with some 360 Jheads. 2.02 valves and the heads have been milled to 56cc Chambers. Stock bottom end, just .030...not decked and i have a compression ratio 9.7:1 and high 13s are expected at my next track outing. I like to consider it 'running good' for what it is. :thumblef:
 
I think your machinist is right on price wise. I have yet to get a good set of heads for under $600..And that's using stock parts. Most of my sets of iorn heads take $800 to get what I consider good. That's all new guides, unleaded seats plus intake seats if needed, Stainless swirl polished over size valves, new name brand springs, cutting down the guides for higher lift, new locks, retainers, teflon or viton seals, and a 5 angle Serdi valve job. These heads will run much better than factory, and last for 100K miles. That's rebuilt to me. Your choice of head, IMO, is ok. I think you could do better in terms of not needing milling of stuff. Basically, the thinking is better port needs less cam, and a smaller port can live witha bigger cam. The cam is ok the way it is, but it would be better torque wise in a 318 sized intake port. You already have the 360 castings, so that keeps costs where they are now. I do think you should mill them if you choose to use them, and dont go 2.02 intakes..keep the 1.88 intake valves. Mill them .040 on the deck surface, and the intake surface, and run them. You will want to pay close attention to the lifter preload when it's being assembled...You may need shims under the rocker shafts to set it at the .030-.040 most guys run. Or shorter pushrods..dont buy them until last. Tha last set of heads I had done for my 360 were '70 318 small open chambers. All done, they cost me $800, and I ported them myself, so that was free..sort of.
 
Ok, so what tell me if I am wrong.

I should get the heads milled .30, new valves (1.88/1.60 ), new springs, new guides and new seats and perhaps "pocket porting"???
 
Yes except for the pocket porting. There should be enuff head as stock to run 12's. Pocket port later if you want, but save the money for now.
 
Ok, so lets try it again.

I should get the heads milled .30, new valves (1.88/1.60 ), new springs, new guides and new seats.

Will I be able to use the stock pushrods? And will I need to have my intake milled at all?

Just questions that are coming to mind the more I read about this process. Sometimes, I think I should not read so much!
 
No, you should read everything. The hard part is deciphering whats helpful, and what might not be. If you mill the deck surface of the cylkinder heads more than .020, you will need to mill the intake gasket flange on the heads, or the intake itself very close to the same amount for the intake to seal properly. IMO, I would mill them further than .020, because any rise in static compression will help in throtle response, torque, and horsepower. The heads need what they need. I always replce guides, mainly because the good machines use a non-tapered pilot to index the seat cutting bit. The straighter and tighter the guide, the more acurate the seat. The better the seat, the more power and life you get. If you have unleaded seats factory, you wont need them. By installing larger than stock valves you can avoid installing seats in some instances. Install 1.65 exhausts. It wont hurt you at all, and will mean the new seat will be up in the chamber, instead of sunk as a 1.60 replacement will need to be. The further out in the chamber a seat is, the more power it will make. Hence new seats when needed. The guides will need to be trimmed down on top if your shop uses guide liners, so the new small seals can be used, and the retainers dont hit the guides at max lift. New locks and retainers are needed because the new valves will use single grooves, and are a different angle than factory..so new retainers and locks go in. Springs to match the cam. 'nuf said. The 5 angle valve job has a "throat cut", and a "chamber cut" in addition to 3 angles. The throat is the area where the bowl turns towards the seat angles. (bowl cleanup is what you said..it's done as part of the valve job..) The chamber cut unshrouds the top valve angle from the chamber surface. A big boost in low lift flow comes from that. Both good for max performance with minimum $ spent. You can use stock pushrods with shioms, or, you can just order pushrods a little shorter than stock. My point was, you will need to CHECK and see how much you'll need to move the rocker to get the right preload and geometry.
 
Moper,

How much should they be milled? And then isn't there an formula for figureing out how much my intake would need to be milled or would I be better off getting the intake flange milled?

Thanks for all your infomative advice!

John
 
POPS6T6 said:
Ok, so lets try it again.
Click to expand...


I should get the heads milled .30, new valves (1.88/1.60 ), new springs, new guides and new seats.

Heres part of the problem in answering you. What comp. ratio are you at now. How far down the hole are the pistons? How many cc's are the 360 heads and what ratio are you looking for?

Will I be able to use the stock pushrods? And will I need to have my intake milled at all?

Depends on the amount milled. Shorter Pushrods are not really expansive at all. Some poeple will shim up the rockers and shafts. I don't like that idea myself. I see it as a band aid fix.
When you mill the heads, you need to mill ethier the intake to head surface on the intake or the intake to head surface on the head. If you do the intake, then that intake is for that head only and you will have to mill the next intake you swap onto it so it will fit.


Just questions that are coming to mind the more I read about this process. Sometimes, I think I should not read so much!

Mopers right. Read read read.

I'll find the formula. It's in the MoPar engines book.
 
Head milling to reduce chamber volume

a. 340 - 360 heads

To reduce the chamber volume, remove .0048" from the head surface per 1 cc of chamber volume.
For each .010 removed from the head, .0095" must be removed from the intake face of the head.

273 - 318 is the same except the .0048" is change to .0053". Thats it.
 
I should get the heads milled .30, new valves (1.88/1.60 ), new springs, new guides and new seats.

Heres part of the problem in answering you. What comp. ratio are you at now. How far down the hole are the pistons? How many cc's are the 360 heads and what ratio are you looking for?

*** To be honest, I do not know the compression ration right now, the block I have was bought and bored .40 with new pistons. I don't have the paperwork on it. The pistons seem to be about 1/16 or so in the block at the highest point. They are Zollner pistons .40 over, and I have not been able to find any information on them.


Will I be able to use the stock pushrods? And will I need to have my intake milled at all?

Depends on the amount milled. Shorter Pushrods are not really expansive at all. Some poeple will shim up the rockers and shafts. I don't like that idea myself. I see it as a band aid fix.
When you mill the heads, you need to mill ethier the intake to head surface on the intake or the intake to head surface on the head. If you do the intake, then that intake is for that head only and you will have to mill the next intake you swap onto it so it will fit.

*** I would think that shorter pushrods are the way to go then. Just makes more sense to me.

and per your formula
To reduce the chamber volume, remove .0048" from the head surface per 1 cc of chamber volume.
For each .010 removed from the head, .0095" must be removed from the intake face of the head.

*** the heads I have are 66.0-72.5 cc and I am not sure what cc range I should be trying to get for best compression on a 318 with 360 heads?

Just questions that are coming to mind the more I read about this process. Sometimes, I think I should not read so much!

Mopers right. Read read read.
*** I am trying it is definately informative and so far has been quite a bit of fun.

I'll find the formula. It's in the MoPar engines book.


Thanks!!
 
Another monkey wrench for you. The head chambers maybe be a bit larger than the published specs. They usually are, for a variety of reasons. The only way to know "for sure", is to have one of the chambers checked for volume (CC'd) before you mill. Also, if you havent measured yet, a fast and easy way (not the most accurate, but better than "1/16 inch down") is to take a metal ruler (not plastic or wood) and lay it on its edge (edge over the piston, parallel to the crank centerline) and use feeler gages to get the thickness of the space between the piston dome and ruler's edge. This should be checked across the center of the piston, in line with the crankshaft centerline. Post that, and the chamber CC measurement, and we can figure out what you need to mill.
 
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