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Head Swap Questions
https://www.slantsix.org/forum/viewtopic.php?t=12368		 Page 1 of 1
Author:  MenkeMoose [ Fri Mar 25, 2005 3:14 pm ]
Post subject:  Head Swap Questions
I have a 1966 Clark Cortez Motorhome which is powered by a Chrysler industrial 225 and a 4 speed front wheel drive transaxle. It has about 88k miles on the original engine.

I read DD's article on the revised combustion chamber of the later heads, and thought while I was doing some other work I would change out the head. I found a new 1983 bare casting for a decent price and thought this would be a good start. I also found new 225 valves on ebay for $45. Can I simply remove all of the other parts from my old head and use them with the new head,valves, and springs? Does everything match up from one head to the other? :? I'm planning to port the head myself, are there other things I should consider changing while the head is off?

The Industrial /6 has a shot-peened cam which I like, so wasn't considering a cam change.

I've been collecting parts to do Bob Dibiase's EFI conversion, and am planning to put it all together with the new head at the same time. I'll also be adding a 2.25" exhaust and a flowmaster 70.

BTW, im looking for reliability and more power going up hill.

Thanks for any advice :D

Moose
Author:  SlantSixDan [ Fri Mar 25, 2005 4:51 pm ]
Post subject: 
Those early Clark Cortezes are nifty. Some things to be aware of with your head swap:

The 1983 head is heavier, runs hotter and has lower compression, and the selection of spark plugs for it is considerably smaller. Also, with the '75-up head you cannot remove the lifters without removing the head, though this isn't such a big deal (how often do you have to service the lifters, anyhow?). The lower compression ratio can be fixed by milling the head.

Yes, you can swap your original head's bolt-on equipment to the new head. But, be advised, the post-'68 combustion chamber by itself isn't worth swapping heads for. It's nowhere near the big change you might imagine it to be. Furthermore, by installing new valves, you're giving up the stellite-faced exhaust valves with which the industrial 225s were originally equipped. Just things to think about.

There were no shot-peened camshafts used in any industrial 225s -- can't think of any other applications that got them, either, for it would offer no advantage. It is the crankshaft that is shot-peened in the truck/industrial 225s. You would be wise to consider swapping the camshaft. An MP244 would probably put a smile on your face, for it increases valve lift for better breathing while not going anywhere near overboard on duration and overlap. These are no longer available from Mopar, but will soon be available again (I just sent my new-in-box example to Doc for his cam grinder to pattern from).

A 2-1/4" exhaust will help, but you may want to look at Dutra Duals, which will help even more. And how 'bout an ignition update?

Remember as you work that most variants of the industrial 225 also got double-roller timing chains and sprockets from the factory, and the heaviest-duty 225-3 engines got Rotocaps (positive exhaust valve rotators) which must be used ONLY with Stellite-faced exhaust valves.

What're you planning on doing with the original sidedraft carb setup once you remove it?
Author:  MenkeMoose [ Fri Mar 25, 2005 5:31 pm ]
Post subject: 
Thanks, Dan, for your quick and awesome response. :D It's especially nice to hear from someone who is familiar with the industrial /6 and the Cortez. Mine does have the double roller timing chain and sprockets. Don't know about the rotocaps. I'm glad I hadn't bought that head yet. I think I'll hold off on the head for now & just focus on intake & exhaust.

I'm still contemplating the dutra duals, since I won't have to worry about intake heating. From most of what I've read here, most people (including Doc) would put them to a y-pipe and single muffler. It seems to me then that the advantage over the stock manifold with a bigger pipe would be minimal. (I would, however, go with these before ever getting headers).

Don't know yet what I'll do with the old intake and side-draft carb... I'd offer it first to fellow Cortez owners who might need it. But otherwise if you want it I'll drop you a note when I'm ready to let it go.

BTW, I've already upgraded the ignition - I used an electronic dist with an MSD 6A, and the MSD off-road coil. That upgrade alone made a big difference!

Thanks again,

Moose
Author:  SlantSixDan [ Fri Mar 25, 2005 5:46 pm ]
Post subject: 
Glad to help out. Tough to say which way I'd go with the exhaust if I were building a Cortez, but I think I'd be very tempted to run Dutra Duals with full duals. That said, a 2-1/4" pipe off the stock manifold will certainly not hurt!

"No carb heat" poses its own interesting challenges. I had Doug build me a special rear casting w/no heat provision (chopped and welded-up the center area) for use with an upcoming twin-SU setup on my '62 Lancer. Without doing that or going to headers (yucky), it's tough to achieve "no carb heat" without a chop-and-weld operation (which you can do on a stock exhaust manifold, too.)

Let us know how your induction project comes along!
Author:  Acuda4me@AOL.com [ Sun Mar 27, 2005 8:28 pm ]
Post subject:  Possible Cortez Engine
Moose-

I just picked up a free 225 slant six that is supposed to be from a Cortez motor home. Other than a bent pushrod, it appears to be okay. Perhaps there are some spare parts you could use. Email me
Acuda4me@AOL.com. I am in Woodland Hills, CA
Author:  MenkeMoose [ Mon Mar 28, 2005 12:04 pm ]
Post subject: 
Thanks again for the help, Dan.

As for my EFI project I've got the injector bungs and fuel rail made, and am fabricating a side mount for the throttle body (all on a 2bbl aluminum intake). I'll post pics when the intake is done ( probably a couple of weeks).

ACUDA4ME: I sent you an email, thanks!

Moose
Author:  steponmebbbboom [ Mon Mar 28, 2005 5:28 pm ]
Post subject: 
Shot peened crank? Stellite valves? Double roller chains? Exhaust valve rotators???

You mean I gotta tear into that engine again??? :(
Author:  SlantSixDan [ Mon Mar 28, 2005 7:33 pm ]
Post subject: 
Quote:
Shot peened crank? Stellite valves? Double roller chains? Exhaust valve rotators???

You mean I gotta tear into that engine again??? :(
Yeah, you better, 'cause if not, your ordinary slant-6 might only last 300,000 miles!
Author:  steponmebbbboom [ Mon Mar 28, 2005 7:45 pm ]
Post subject: 
I'm planning for my retirement!!! :lol:
Author:  Jeb [ Tue Mar 29, 2005 6:40 am ]
Post subject: 
Did slants ever come with sodium filled valves?
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