HEMI Tech- Block, head, porting/polishing, and gaskets

Seems like every part of a Hemi is MASSIVE! Especially the block and heads! Still, there are things to look for when rebuilding and things that should be done to get them ready for those desired rebuild components.

1) The Hemi Block...
- When should magnafluxing be done?
- When will main caps need to be modified?
- When should the cylinders be sleaved?
- What freeze plugs should be used and why?
- What should be considerd with oil passages and the water jacket?
- When should a line-bore be performed (if ever)?
- Any other modifications to consider?
- Block coatings for final appearance?

2) Heads....
- What heads will work on what motors?
- what components will interchange between heads of other makes?
- When sould magnafluxing be considered for heads?
- what things will require attention when considering a head rebuild?
- what should be looked at in the combustion chambers?
- Who makes aftermarket heads and for what makes and models of Hemi Engines?
- Head coatings ouside and in the rocker areas?

3) Porting/polishing...
- When should porting and polishing be performed?
- Who should do it?

4) Gaskets...
- What gaskets should be used?
- Who makes the best gaskets and where can you get them?
- Other sealants or compounds required for your rebuild and for what areas?

5) Mounting
- Bolts & Fasteners

 

Obviously this ALL depends on your final useage, but for my street duty (light strip duty) here's my rules of thumb for a early hemi. (fwiw)

Magnalux - if the budget allows (usually it didn't) - but definitely do it IF you're spending any real dough to build the motor - cheap insurance. Admittedly I skipped this step quite often - but the blocks all LOOKED fine - no signs of damage and they weren't Hot Rod motors to begin with. Today I would sing a different tune though.

Modified caps? Do you mean cutting them for girdle or straps?? If so then I'd say again Cheap Insurance but not needed for a street motor.

Freeze Plugs - always ran stockers on the street - admittely they aren't any too impressive - If I was serious I'd bore them for CUP style plugs or spring for those fancy ones.

Align bore - Race motor - maybe - street motor - why bother. Now IF I had funny bearing wear I'd reconsider my position.

Heads - prone to crack between spark plug and valve - bad on a street motor - not so bad on a race motor.

Heads - Scronge the swap meets - lots of early iron heads were really well race prepped by a myriad of shops - I once stumbled on a set of Mondello's CHEAP beacuse they were IRON and obvioulsy not anything real good!!!!

Rocker arms - same thing - the "shiney" ones are always expensive, but deals can sometimes be had on Gotha's and even Donovan's as they aren't as noticeable as the Aluminum ones. Sure it's tough for that to happen today - but it still does. If you're Diamond Jim - you can spring for a nice set of Titan's - for a few grand of course. Lotsa old fule motors simply ran polished and balanced stockers. "hot set up" often include stock intake rockers and aftermarket exhaust since those were prone to break.

Street porting (IMHO) should only focus on removing a BARE minimum of material - basically just clean up any flash - no need to "open them up" - leave that for the strip.

Now again - everything hinges on YOUR intended use and budget - you can spend a fortune or do the minimum - how deep are your pockets??

 

alright, here's a question for you guru's out there...I've got the '53 early heads with the small round exhaust ports...in '54 they opened them up to the later square style...is there enough material there to machine out the round style exhaust ports to the later square style ones? I wanted to swap to the '55 and later heads, but money won't let me...and the fact that I found an early U-Fab for the "wet" intake style heads, so I'm keeping the '53 heads, and would love it if I could machine the exhaust ports larger...thanks

 

The best heads are the new aluminum that flow better than the cast heads but who has the coin for those. The 55 331's are supposed to be the best flowing heads of the cast. Mine is all 392 a hemi head is good not matter what you use. Also I used studs for the mains and heads for added strengh. And one of the most inportant areas to remember is sealing the threads attaching the valve covers and the headers they are open to oil drain and water passages and use the high temp stuff. Yesterday I pulled my valve covers to adjust my valves and forgot to drain the antifreeze and when I pulled the top bolts the antifreeze ran out the hole due to the fact I had the car jacked up.

 

now THAT'S a good tip, seal your studs and bolts...nothing worse than getting a motor together and fired up for the first time and watching fluids drip all over the place...

 

Actually what's even BETTER than that is to go and install some extra short set screws. I re-tapped my heads - bottom tapped them for the extra room to install a short stainless steel set screw (with sealant of course). This way I can use the old tall boss valve covers with long bolts and disassemble everything without any leaks. At least for the valve covers anyways!

 

HemiRambler,

You know I was thinking about that today after all the antifreeze I put on the floor. Did you use set screws in the header attachment holes also? I've had to reseal those twice since I put the motor together (2 1/2 years ago). What sealant did you use? I'm using this high temp coppered color permatix product especially on the header bolts.

 

Supposedly, the "555" heads are the best performing ones. It's also said that the low deck heads perform better than the high deck.

If you're running moderate to high boost, it's a good idea to have youe heads o-ringed as well

 

with the valves out, on the 55 & 56 heads, you can look in the intake port & see out the exhaust ports. Not so strait on the 392 heads. But...In Tex Smith's book Don Garlits said he doesn't bother to change out 392 heads...

 

Seen this asked somewhere, but don't remember seeing a responce..Is the 301 a really underbored 331, or did they adjust inward the O.D. of the walls?

 

My current project has an IND-56A block (A-1 casting) and '55 high port (555) heads.

The block is bored, line-bored and decked. Mag'd...stock caps. Head and main studs.

The heads were mag'd and surfaced, stock rockers, stainless valves, steel retainers.

I had everything done per my engine shops recommendations....

 

Your crappy old style heads will outflow most any stock wedge head in existence...don't worry, be happy

 

So THAT'S why they come stock with studs in the top three holes....

 

4tford, I'll have to take a look - whatever it was it has been pretty good as I haven't fiddled with them in many years. I seem to recall just using that red/brown colored RTV on regular header bolts. I don't remember putting the set screws in for the headers - just the valve covers. I don't remember if the heads have enough thread depth to do this or not. I'll look mine over tonight. I know for certain that the heads do - but not by alot - I used RTV on the set screws been fine - but the last sets have only been done for a few months now.

On the set of zoomies I just did I used regular header bolts, but man they are close as the tube size is kinda big. I know I had to "oval out" a couple of the holes just to be able to get the header bolt started. No antifreeze to worry about on THAT one so nothing's fresh in my mind.

 

Seems like that was a good ideal oem. I'm either going to use set screws or studs that is for sure. I chalk it up to one of lifes lessons good info.

 

Discussion of '57-'58 354 truck/industrial/marine heads on an early 331 block here:
http://www.jalopyjournal.com/forum/showthread.php?t=136238

 

I am building a blown street 392 hemi and I want to beef up the mains. HP will be approx 650-1000 I dont want to use the stock caps but someone told me to get the 2 bolt pro-gram billet ones and use studs! i dont like the idea of using 4 bolts mains due to the thin webs and going into the water jackets. Can anyone give anymore advice? Thanxs

 

They are oval, not square.

 

yeah, they're oval...but nobody answered my question...so I wound up getting small primary headers that match the stock round ports and that'll have to work...I just hope she can push enough out...at least I'm not supercharging it...

 

Sure, build a girdle.

 

Here's something for you to check out... Maybe something like this would work for you. Good topic!

http://gearsandrears.com/girdle.html



Obviously it would NOT work like this exactly (not a Hemi in the picture) because of how the caps are positioned on the block... but just food for though. Or maybe something like this...

 

You should be able to use stock caps.
Ive got a couple of sets of brand new Ansen straps & studs for a '92.
Alot of TF guys used them way back when.
Check your PMs.

 

A lot of records were set by the 51-53 engines.

 

but did they retain the stock heads? another thing I want to do away with is the stock timing cover, but I want to retain the fuel pump location (which apparently nobody makes a short cover with the stock fuel pump location)...

 

How many of you convert to studs for your main caps? Any advantage other than just making it easier to mount a windage tray?

 

main cap studs help keep the crank from walking, or at least that's what the manufacturers claim...but I could see how the stress/tension of a nut and washer versus a bolt head and washer could be different, and could ultimately "capture" the main cap with more force using a stud and nut/washer...and I'm sure a nut has more surface area than a bolt head...

 

According to ARP, advantages of main cap studs over bolts are:

1. More accurate torque readings
2. All clamping forces on one axis
3. Less force exerted on block threads
4. Easier engine assembly and proper alignment of caps

 

I left part out. A lot of records were set by the 51-53 engines in 51-53. My understanding is that most of the improvements were more carbs & more cam vs stock (probably higher compression) no head choice then! I think you have to use stock timing cover if you want the mech. fuel pump on the 51-53s. However, Someone had a picture here of a vintage aftermarket timing cover that looked like it could be drilled for either bolt pattern. If you can drill a 55 cover with the early pattern (or modify one), you can run a long BBC water pump w/adaptor with the stock cover on a '55 331, so it might be doable on the earlier ones.

 

I remember that cover also! Who had that? Was it Bass? Clark maybe? Can't remember...

 

Think it was Wieand. That one was like the HH one, no provision for fuel pump.