Recommend Head Rebuilding

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1973_Scamp

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Hello FABO
I'm the the process of getting a "308" heads to the machine shop. These heads will seat on stock bottom 318, 904 transmission, and 7.25 rear. These are parts that I've been collecting so far:

  • Procomp distributor
  • Procomp E-Coil.
  • Edelbrock 1406 Carburetor.
  • Edelbrock 2176 Intake manifold.
  • Hedman block hugger exhaust manifod.
  • 273 Roller rocker with spring and push rod
  • 308 head
  • High Torque Mini Starter
What are the recommendation things to do for these head?:violent1:
Also, please recommend bottom end work and Cam-shaft for future tear down.

Thanks,
 
I wish I could say I was more familiar with that casting number-are they open chamber type smog heads? As with any stock head, it depends on what all you wish to accomplish. If you're running a stock bottom end 318, just a simple overhaul should suffice...good 3 angle valve job will help low and mid lift flow and improve the off idle torque and acceleration. If they are open smog heads, I'd almost say have them shaved a little to close up the chambers and yield a little higher compression.

Do you know what kind of cam you want to run?
 
The 308's are an open chamber smog head with 360 sized ports, but had redesigned exhaust ports that flow quite a bit better than earlier designs. Kind of a precursor to the Magnum head exhaust chambers.

They can be made to flow as well/better than the earlier heads, I have a ported set of 308's on my 340, they flowed 264 cfm at .500" on the intake side on my machinist's flow bench. In stock form they're pretty comparable to 1.88"/1.60" J heads, just with slightly better exhaust flow #'s.

But, for a stock bottom end 318 I don't think they're the best head out there. 302 heads would be a better choice, they're closed chamber and have a similar design exhaust port. They have the smaller 318 ports, but for a stock 318 that's a good thing to maintain port velocity. The 308's will lower your already low stock compression because of the open chambers, and the large 360 ports will reduce flow velocity.

For a 318 with aftermarket pistons and a hot cam, I could see using the 308's, or any 360 head for that matter. But for a stock bottom end with ~8:1 compression, the open chambers will kill your compression. The 308's would need to be shaved pretty significantly to get the chambers small enough to maintain or improve your compression ratio, as the 308's chambers are 65-72cc's depending on the casting.

The rest of your build seems fairly mild. Not a bad thing, but the 308's will be overkill in a big way. The compression ratio is going to be a big issue with a stock bottom end and those heads. What are your plans for the car? Just wake up the old 318?
 
That's a pretty nice little street cam-if you're planning on running that one, I'm with 72...might wanna choose some different heads...you'd probably have to advance the cam about 6-8* to have any kind of low end because of the static compression being so low with the 308 castings. "302" heads would indeed work to keep your compression, but if you're going to go the trouble of swapping heads, consider magnums and convert the top end to accept it, or EQ mags with the LA bolt pattern.

A stock bottom end 318 usually has pistons about .040-.060" in the hole...assuming that, a true 62cc chamber with .040" head gaskets would net you ~9:1 CR...and that should be enough to make some decent use of that cam. Now, all that being said, you'll still need to have the heads checked out for the cam (maybe spring change). And you still could benefit from advancing the cam a couple degrees.

Do yourself a favor and make use of that search function-there are dozens of folks on here who've had the same or similar questions when building up a 318.
 
Why do people slobber all over the edelbrock performer TURD intake? I just don't get it when the Weiand Action Plus is SO much better.
 
I didn't see anywhere him slobbering over it, clearly the Weiand is a better piece, but different strokes for different folks...and he already has it...
 
Guess one of us should've asked first off-what are your overall goals with this build?
 
txstang84 said:
Guess one of us should've asked first off-what are your overall goals with this build?
Click to expand...


This is just a street build, weekend cruiser. I also have stock "302". The though is to have 308 rebuild with 2.02" intake, 1.60" exhaust with mild bowl port for future bottom end upgrade or 360 block.
I could rebuild "302" as well, then save "308" for future swap. Most head rebuild cost ~$500 per pair. I'm trying to go "green"
 
308s are a great head but save them for your 360 . a stock 318 will run like a lame dog with bad breath
 
Nuthin special at all about the 308. They are the same as anu other open chamber, 1.88 intake valve small block MoPar head.
 
RustyRatRod said:
Why do people slobber all over the edelbrock performer TURD intake? I just don't get it when the Weiand Action Plus is SO much better.
Click to expand...


So, at the end of the day, what are the differences on a 318/340 Performer intake on a mild street 318 vs the Weiand?
 
I kept my stock bottom end after teardown of my 318. My pistons were .040" in the hole but rings were good. To help things out, I went with warmed over 302's. 1.88"/1.60 valves with some unshrouding & mild bowl work. .028" head gasket and the same cam you referenced(xe268 ). I have the Performer intake, but wished I would have went with the Weiand or the M1/stealth, I would have went that way. I run a Holley 600 vac & matched it up with Hooker Comps & 2 1/4 dual exhaust.

I'm extremely happy with the 318 & didn't spend much money at all. Night & day between day one performance & what I have now. The only thing holding me back is the 2.76 gears in the back. I'm building an 8.75 suregrip now with 3.23 gears & expect that to pair up well with the 2200 stall & TF-2 shift kit. Should be a nice package for a cruiser and I feel the components compliment each other well.

I would try to talk you out of those open chamber heads, though. Good luck with your build.
 
eestatic said:
So, at the end of the day, what are the differences on a 318/340 Performer intake on a mild street 318 vs the Weiand?
Click to expand...

I tell you what you do. Go find a good picture of each one. Look at the runners. If you still have questions, let me know. Not bein smart, but a picture is worth a thousand words.
 
I'm no tryin to dump all over your intake choice here. But the Performer is more in line with upgrades for a bone stock engine.....say for instance on a truck motor. They will enhance bottom end torque in that situation. My reasoning for the Weiand is simple. It's a better intake without having to plunk 300 for an air gap, and it can stand more upgrades in the future whereas a Performer would be holding you back with future upgrades. Does that make sense?
 
1973_Scamp said:
This is just a street build, weekend cruiser. I also have stock "302". The though is to have 308 rebuild with 2.02" intake, 1.60" exhaust with mild bowl port for future bottom end upgrade or 360 block.
I could rebuild "302" as well, then save "308" for future swap. Most head rebuild cost ~$500 per pair. I'm trying to go "green"
Click to expand...

I'd put the 302's on the stock 318 bottom end. They should improve your compression ratio a bit, and the small ports will keep the velocity up. The rest of the build is pretty mild, so I wouldn't even bother with larger valves in the 302's unless your valve seats already need work. Keep them plain and save the upgrade money for the 308's later.

RustyRatRod said:
Nuthin special at all about the 308. They are the same as anu other open chamber, 1.88 intake valve small block MoPar head.
Click to expand...

Not true. There isn't much different, but the exhaust port has a better design and flows better than the older J heads. Intake side is pretty much identical. But there is a reason why folks were swapping J heads for 308's before all of the aftermarket heads came out.

That said, given the aftermarket heads out there now though I wouldn't mess with porting or doing too much work to a stock set of heads. By the time you've gotten decent numbers out of them, you could have bought a set of EQ's, RHS's, or even Edelbrock's depending on how big you went. I had the 308's ported for my 340 before the RHS's came out, and I needed an open chamber because the early 340 and KB's I already had put the piston's .018" out of the cylinders. But by the time I had them flowing 264 cfm I could have bought a set of RHS's and had the chambers clearanced or 340 Edelbrock's and had even more flow.
 
72bluNblu said:
I had the 308's ported for my 340 before the RHS's came out, and I needed an open chamber because the early 340 and KB's I already had put the piston's .018" out of the cylinders. But by the time I had them flowing 264 cfm I could have bought a set of RHS's and had the chambers clearanced or 340 Edelbrock's and had even more flow.
Click to expand...

Message is well delivered. That wouldn't be no fun and little to learn. Don't mention about crate engine. I know nothing about engine and I'm teaching my 12 years young boy how to rebuild engine with a manual.:newb:
 
RustyRatRod said:
I tell you what you do. Go find a good picture of each one. Look at the runners. If you still have questions, let me know. Not bein smart, but a picture is worth a thousand words.
Click to expand...

Not to hijack this thread, but are there any Dyno tests side-by-side comparing the Weiand to the Edlebrock on a mild 318 build available? Just how much are we talking about here?

Curious..

Thanks for the input
 
The RPM Air Gap has been top of the heap in terms of dyno testing since it came out. The weiand Stealth is good - but isn't as good in terms of back to back dyno testing. Do a search on small block intakes... It's well known.
 
Sure moper that kinda goes without sayin. But not everybody has 300 plus clams to dump on an intake.
 
72bluNblu said:
I'd put the 302's on the stock 318 bottom end. They should improve your compression ratio a bit, and the small ports will keep the velocity up. The rest of the build is pretty mild, so I wouldn't even bother with larger valves in the 302's unless your valve seats already need work. Keep them plain and save the upgrade money for the 308's later.



Not true. There isn't much different, but the exhaust port has a better design and flows better than the older J heads. Intake side is pretty much identical. But there is a reason why folks were swapping J heads for 308's before all of the aftermarket heads came out.

That said, given the aftermarket heads out there now though I wouldn't mess with porting or doing too much work to a stock set of heads. By the time you've gotten decent numbers out of them, you could have bought a set of EQ's, RHS's, or even Edelbrock's depending on how big you went. I had the 308's ported for my 340 before the RHS's came out, and I needed an open chamber because the early 340 and KB's I already had put the piston's .018" out of the cylinders. But by the time I had them flowing 264 cfm I could have bought a set of RHS's and had the chambers clearanced or 340 Edelbrock's and had even more flow.
Click to expand...

Define. "better". You got flow numbers? He'd never feel the difference between the two heads unported. Never. No how. No way.
 
You're right - but your point seemed to be look at the ports and they're better. I don;t think the evidence proves that. The Stealth is good and I agree - one in the hand is always cheaper than buying anything...lol. But IMO it's not as good as that $300 spend. If you have to buy something it's money well spent.
 
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