Blown Desoto Hemi tech (porting heads)

Ok some of you guys may know that Im putting one of these engines together for a future project, so I Im kinda treating it as a mini project in itself if you will.

Its a '56 330 DeSoto Firedome, plans call for a 6-71, 8-10 psi, 4 x Stromberg WW, BB Poncho H beams, Arias forged slugs, head/mains studs, SB Mopar oil pump, gear drive, Herbert juice roller cam, Comp hyd roller lifters, ported/oringed heads, MSD ign etc etc.

I already have a lot of the parts I will need, but it won't be a cheap deal either way. Thats OK, as its'll be a kinda long haul deal/project anyways.

So Im breaking the project down to its various components and doing what I can to keep costs down. Atm, i have an abundance of time, but not too much disposable $$$, so Im using the time effectively to do what I can.

The block is primo - I have never seen such a clean Mopar casting, virtually zero flash and it took 5 mins to clean it up with a die grinder. The water jackets are among the cleanest I have seen, esp on avintage engine - bugger all pitting on the water jacket, I guess I lucked out coz this engine seems to be a low mile deal, judging by bore/valvetrain wear etc.

So being an anal bastard, I dropped the block into the molasses soup for a month, then pulled it out to hose it off and check it. Ultra clean. Silver water jackets/block/valley. Then I dropped it in for another week before I remove it for final cleanup and and internal/external paint.

So getting to the heads - Im shooting for approx 525HP+ and 500ft/lbs TQ. The cyl heads have a limited cross sectional area compared to Chrysler 354/392, so they will need some work, but I am being careful to not go silly and trash a nice set of heads. On the plus side, airpseed will be killer with these heads, esp when you add the blower into the mix. Good for TQ. Even though I have a lung forcing air/fuel into this thing, I don't want turbulence in the port creating flow issues, so ive been very careful with the heads.. As it stands , I have done bowl blend, cleaned up the short side radius and have gasket matched the intakes to about 1.5" into the port. Port walls have been left at around 60/80 grit for good fuel atomisation.

On the exhaust side, I have blended the bowls, polished the port to 120 grit, have radiiused the guides and tried to leave enough meat for hardened inserts. Once the inserts go in I'll clean up any leffover ledge with the 80/100 cartridge rolls. Lastly,a port match the exh port to the headers when I get around to fabbing them up....

On the head topside, it was cleaned, the oil drainback holes slightly radiisued and was painted with Glyptol to assist in oil drainback.

When finished, I will be using Ferrea 2.00"/1.75" valves with 11/32" stems - the factory guides will be K lined to step them down from the factory 3/8". Mostly likely will run beehive springs with the juice roller.

Any input form the Hemi guys would also be much appreciated....Scoot,DeSoto ?

Pix to follow, stay tuned.....

Rat

 

Sounds like you are doing everything right.
The only thing I can add is, I have a friend that lost a head off of a Ferrea valve. He was driving behind me just cruising on a back road quite slow, when it let go. Fortunatly it didn't cause much damage because of the low RPM at the time.
It was on a blown 354.
I don't know if Ferrea have many problems, maybe someone else will chime in on this.
HemiDeuce.

 

Ferrea no. the guy cutting the lock groves yes also the guy clearancing the motor yes but Ferrea no. many years using them in very high demand situations. ok back to that Rat bastad you go brother i'm right behind you building the same piece. i think you should leave the heads the way you have them now no more massaging the blower will do the rest ..

 

Didnt know there were issues with Ferrea valves. Its just that I found the valves that I believe will suit my needs for length, OD, stem diameter, installed height etc. Anyone else know of issues with these valves?

Thats it for the heads....you are correct, the blower will do the work. I just wanted the forts to flow well without casting irregularities and impediments and maximise the combo considering the cam upgrade too.

Lets see, Manley, Milodon, REV, who else amkes decent valves?

HEMI guys....jump in !!

BTT

Rat

 

Have you seen the NOS Desoto oil pumps on ebay. $129.95 I don't know if it'll fit. It's for a 57-58 hemi.
Good Luck.

Lucky667

 

i would be very carefull about machining in seat inserts on exhaust seats as there is very little meat on short side to work with. i have had good luck with manley valves.

 

Ferrea valves are a quality piece! I have them in my race engine & I beat on them every chance I get! You will hear stories about every engine component manufacturer but seldom the whole story! BTW did your 330 have the typical hemi sludge under the valve covers etc when you torn it down??

 

Hemi35, there was some sludge but not a huge amount jsuging from waht I could see in the pix I had before it was baked.

As for the Ferreas, I havent heard of any issues before either....one of those deals I guess.

Hemihiboy, my understanding is that the fitting of hardened inserts is a no brainer. What is the real issue on the short side? Are you saying that by boring the seats fpor inserts that you can get close to water?

Rat

 

RAT - Just a runner clean-up/bowl blending/gasket match is all that you'll need on the intakes. The key to a good blower install is exhaust system work...starting at the heads. GOOD idea to polish up the exhaust side. The Blower will stuff the mix in, but any help you can give the exhaust side will help a lot...no blower to help, on that end. Not many people realize the reason the Hemi's are such killer engines is the flow characteristics of the heads...STRAIGHT in/STRAIGHT out and the "hemi" shaped combustion chamber. As an aside, got sick of sitting around and ordered my Frame, yesterday. I STILL need a measurement from the front of the bare block to the front face of the fan on a DeSoto engine...preferably 276/291. Maybe a 330/341 is the same.

 

Thats exactly what Ive done 345 - polish the exhausts,clean up the short side radius (a lot of casting flash/ridges here) and contour the guides as well as match the ports to the headers.

I realize the ports are straight in/out, which is why they work so well with a lung hehe. Infact, the exh flow close to 85% of the intake STOCK. Not bad. But we can do better right? And that custom ground tick will help ......

As promised here are soem pic of the stock head - intakes and exhaust ports and chambers....

Follow along as hopefully the pix will show what has been done !!

Rat

 

Starting on the intakes, I cleaned up the short side radius and and the bowls as well as port matching the heads to the gasket. They were close but still needed some work to be right.

Then cleaned it up aboutabout 1.5" into the port with 80 grit cartridge rolls. They cleaned up well.

Rat

 

RAT - That's awfully nice work...

 

On the exhausts.....short sides, bowls (pretty ragged ex factory) and port match as well as a thorough polish.

The next step when $$ permits is to get the inserts fitted to the exh valve, the seats cut, guides K lined and decks mildly cleaned up. Still need to get the valves first though hehe. We'll get there.

Overall I was really impressed with the castings - the chambers are super sano ex factory and will polish up killer with 160-180 grit flap wheel. Nice.

I forgot to mention that I extracted quite a bit of wire from inside the heads water jackets - wire which I assume was used to hold the mould together when the heads were poured. The dunk in the molasses batch cleaned up the water jaclets real nice and freed up most of that wire so that it could be removed. Interesting....

Rat

 

Hey, that's lookin' pretty good man! What did you use to get into the combustion area?

Is this the motor from Denver?

 

WOW! very nice ....

 

Yeah Scoot thats the one !! I guess I lucked out so far on tha shape its in!!

Yeah mean the combustion chamber? Well on this Hemi, its actually machined, NOT cast as most engines are, so it is super clean and an ultra light flap wheel in the die grinder will make the chambers looks like mirrors haha.

Have'nt done 'em yet - need another lite grit flap wheel so I don't remove any material. Ill simply fit the old valves to protect the seat areas and polish 'em up soon.

Mght have install the valves with a light grease to seal them, borrow a mates burette to cc the ports and ensure theyre all eqaul

Ahh so much free time, so little $$$ hahaha

Rat

 

Right, right. Cool! No pitting is amazing!

Thanks for sharing! I would appreciate it if you would keep the DeSoto tech stuff going! I know there are a ton of people sitting around with DeSoto Hemis that read through the Hemi Tech stuff and find very little that is of any benefit to them. Even the most basic stuff you can share would be an asset.

In the mean time, I've added the link to this thread in the right catagory. Again, thanks for posting this.

 

No sweat Scoot - Ill keep the updates coming as we make progress.

Im enjoying wrenching on this engine...its so different to the wedge stuff ive played with yet the blocks are almost like small block MoPars, so nothing new there for me hehe.

Ive done some scoping, testing, fitting and Ive found the following stuff fits the tall deck Desoto well, even with a little tweaking :

i. ARP Small Block moPar mains studs...a little longer than required but OK
ii. Mildodon/Diecrest Engineering SBM single idler gear drives
iii. Rollmaster SBM timing chains/gears
iv: SBM HV Melling oil pumps with Hot Heads Adaptors,....more on that later.
v. ARP Chrysler Hemi head studs...again a tad longer then the Desoto one (measured) but more than
suitable enough for the DeSoto.
vi. SMB distributor with Hot Heads adaptor (or modded 1/4" longer dist shaft)
vii. Ferrea makes a 2.00" 11/32" stem valve that is close to the ideal length and an exh
valve to suit a 351 Cleveland 1.75" 11/32". The 2.00" int valve is slightly larger than
the factory 1.94" 3/8" vlave. This saves some weight as well with the 11/32" valve
being lighter. Less valvetrain mass can't hurt.
viii. Pocnho/Injun BB400//455 H Beam rods also fit. Same centre to centre length, pin
end can be redone to suit the Desoto slug OR Im thinking Ill use a smaller SBC pin
with the Arias slugs and re bush the rods to suit. less weight and more strength
with the H beam. they will need .005 - .010" off each side for rod side oil clearance.
This clearance is to be confirmed.....

As I find out more info, I'll post it up, hopefully the other DeSoto guys could find it useful.

Cheers

Rat

 

Rat, be sure that you are very comfortable with the sbm oil pump install...there are issues with shaft alignment which can cause problems. Why not use an oem pump? According to Melling test reports the output is essentially the same and you don't spend money on adapters.

Gary

.

 

Thanx RR,

I have been made aware of the shaft to cap dowel alignment issues. If push comes to shove Ill use the OEM pump, even with a slight shim for a llittle more.

We'll see.

I wonder if Bob from HH is reading this - if there have been so many issues, he needs to KNOW about it and take corrective steps to fix the adaptos to align the pump correctly?

Surely theres plenty of dudes running the SBM pump and HH adaptor without issues too? If so then the problem could be in the accuracy of the adaptor used or the ID thickness of the OEM main cap dowel relative to the pump shaft.

I wonder....

Rat

 

While we're at it, will a 392 distributor fit/work in the Desoto? I've heard all over, that you can't interchange a short deck (276/291) DeSoto distributor with a tall deck (330/341) DeSoto distributor...guess what. It's not true. I'm using a short deck Desoto distributor in my 345, and the fit is perfect...and works fine. Would the 392 distributor be too long, OAL? If so, a collar of the appropriate thickness might be the answer...

 

Since you're running a blower, you might want to consider o-ringing the block and heads to match. It does help if you're going to be putting any real boost to it.

I've not built a Desoto, so I don't know what head gaskets are available - I'm using some rubber coated copper ones from 'FlatOut'. I've not fired the motor as of yet, but these gaskets come highly recommended - especially when running O-rings and needing 'wet decks'. Lots of guys forget that the O-rings and gaskets that work for a dry-deck top-fuel motor may leak water/oil on a wet-deck setup (street).

Keep us posted . . . nice work!

Dale

 

Hi rat, don't know if you read this thread: http://www.jalopyjournal.com/forum/showthread.php?t=329690

...some good back and forth.


Gary

.

 

B&S Ill be O ringing the heads yes.....we have a local mob here that make copperhead gaskets in any thickness required. They come with a coating to seal wet deck street engines.

The next option would be best gasket, with Coppercoat....hmmmmm

With 4 studs around each cyl bore, it is normally harder to seal high boost engines on paper. In reality, Ive never had an issue.

Timing control as boost rises is key here. MSD 6BTM I have will come inhandy no doubt.

345 I dunno about the fit of a 392 dist in the tall deck Desoto.

B&S how is that beast of yours coming along man ?

Rat

 

It is always slower than one would like -- but I guess the only good side is it spaces the "money flow" out a bit. I've been working like mad on my frame/chassis - am working through the X-member setup in the middle, the brake/clutch pedal setup, etc.. With the engine back about 4 inches (room for blower pulley) - what a BITCH it is to get everything to fit! The Donovan 417 heads make everything all the more difficult - looks like my brake pedal will clear the head by about 1/2" (the pedal axis/rotation point is about 1.5" back). I spent two evenings just moving things around, coming up with ideas on how to tie the x-members back to the side rails and get by everything, etc.. I should have everything mocked/tacked in this weekend . . . will update my frame thread. The BEST decision I made was to quit thinking I was going to build a set of inside the frame headers - with 2.25 primaries . . . not a F***ing chance. Now that I've decided to build Lakes style pipes, that drama is out of my brain.

Hope to fire the motor this summer!

 

2 1/4" primaries off the Donovan head INSIDE the frame? What, arent you gonna run a steering shaft or have any ground clearance hehe?

Maaaate, I knew you'd nut out that you'd be pushin shit uphill with that one haha !!

Why the 4" setback?

Can you not run a shorter snout on the blower for rad clearance.? what kinda mounts did you end up using and where are they mounted to the frame?

Pix?

 

I need about 8" of clearance from the front of the block to clear the blower pulley and have a little left over. This means moving the motor back about 4" or so (somewhere between 3" and 4"). 1934 coupes have NO room in front - even with a flathead you only have room for a 2 v-belt pulley in front!.

I'll be making the motor mounts myself -- may also have a mid-mount that picks up the 'ears' I had designed into the Wilcap-to-sonic adapter plate. I'd like to take a bit of weight off of the trans mount. I'll be working this out in the next couple weeks. I also am having a custom 34 radiator made (brass) - and will move the upper water necks as far out on the tank as possible - to clear the upper blower pulley. Tight bastard that it is! (I'm running dual water outlets - one from each head, like an old flatty!).

 

Ok B&S Im with ya....

More updates to follow....

Rat

 

I have a tip given to me about 330 Desoto Hemi's by someone that use to run them on the drag strip back in the day, his name was Sam McQuagg, I met him at the swap meet in Moultrie, GA Nov 08, where I had a Desoto Hemi for sale, he told me the he had a lot of problems with oiling on the bottom end until he got a tip from other drag racers, he said that you need to drill, tap and plug the oil passages in the block then drill the plugs to a smaller size, after that he didn't spin any more bearings. See if anyone else has done this, or if you need it for your application. One more interesting thing about meeting Mr. McQuagg, as he was leaving my space he told me he won the 1966 Fire Cracker 400 Race in a 66 Charger, it was cool meeting him, I was sorry to find out when I went back to Moultrie this Feb that he had passed away.

 

I have a tip given to me about 330 Desoto Hemi's by someone that use to run them on the drag strip back in the day, his name was Sam McQuagg, I met him at the swap meet in Moultrie, GA Nov 08, where I had a Desoto Hemi for sale, he told me the he had a lot of problems with oiling on the bottom end until he got a tip from other drag racers, he said that you need to drill, tap and plug the oil passages in the block then drill the plugs to a smaller size, after that he didn't spin any more bearings. See if anyone else has done this, or if you need it for your application. One more interesting thing about meeting Mr. McQuagg, as he was leaving my space he told me he won the 1966 Fire Cracker 400 Race in a 66 Charger, it was cool meeting him, I was sorry to find out when I went back to Moultrie this Feb that he had passed away.