I'm trying to determine if the twin Weber downdraft and intake manifold for the
Chrysler Slant six engine or the "Hyperpack" manifold will fit where the stock intake and 2 barrel carb
does. This particular engine is in a 1965 Turbocraft jetboat and there is
very limited space underneath the engine cover. Does anyone have physical
dimensions of either the twin carb intake manifold or the "Hyperpack" intake manifold that you could send me ?
Thanks in advance,
John J. Garber


tirebiter@compuserve.com

John sent-in additional pre-rebuild test info which we will post here for everyone.

John seems like he is pretty knowledgable and wants to do things right.
Everyone please help us out with ideas and answers while I collect some additional info to post. (see John's latest info below)
DD

...Performed a cylinder leakage test to get some idea of the condition of the Jet Boat SL6 engine. The thing is completely worn out, amazing that it still ran at all! 100% leakage on 2 cylinders, best one had 80%. All cylinders had bad exhaust valves, probably due to using unleaded fuel in a 1965 automotive engine.

I'm preparing a complete rebuild/modification plan for my customer so that I won't get deluged with changes after I start in on the rebuild job.

I do have a question about the normal direction of rotation for the engine. Does the crankshaft rotate clockwise or counterclockwise, when viewed from the front of the engine ?

Also, what is the standard horsepower rating and at what RPM for the automotive equivalent of this 225 cubic inch /6 engine ?

After seeing the results of the cylinder leakage test, I'm thinking that it won't be very hard to get enough power from this engine with only some slight modifications. Perhaps a bone-stock rebuild is all that is needed with the addition of unleaded compatible valve and seat components.
Any Inputs?

I'd like to increase the power and the customer is certain he wants more than stock performance.
In your opinion, is 200 to 225 horsepower attainable at 5000 to 5500 RPM with the limiting water-cooled exhaust manifold, running on 90 to 92 octane gasoline? I have gotten differing reports of what the stock HP rating is, 150 HP, 170 HP ...? at what RPM?

It turns out that I can't put the engine on my engine stand and will have to make/modify a stand just for this job. The rear engine mount is attached to the bellhousing and the front mount is attached to brackets in front of the timing cover. Do you have any suggestions where on each side of the block, should I bolt-up to make the engine stand?
Which holes are the standard engine mounting locations?
Jeff Garber

Here is a PIC of the most popular SL6 intakes.
The Hyper-Pak is the long runner unit at the lower left and as you can see, this will not fit into any "limited space" location.
I would think the dual carb manifold would fit as well as the 4 bbl unit shown.
You could even put a larger 2 bbl carb onto the current manifold and get a good increase.
DD
PS, the manifolds shown below are: (starting at top, clockwise)
Factory Alm. 1 BBL, Clifford Triple Webber, Clifford 4 BBL, Factory "Super Six" (Iron),"Repop" Hyper-Pak, Offy Dual 1 BBLs (can be opened-up for 2 BBLs or Webbers)

Doc,

that's a pretty cool picture. I'm kind of curious about the one that's second from the top on the right. What is it and where did it come from?
(who cast it, what do you install on it?)

TIA

-D.Idiot

res0aus2@verizon.net

Thanks for posting the the pics Doug. The 4-bbl manifold looks like it actually has a large plenum. Are the runner lengths in the 4-bbl manifold more closely matched than in the stock 2-bbl manifold or is it just an illusion ?
It is now clear to me that the triple Weber setup is out of the question as is going with multi-port EFI. My customer told me very recently that he wants to be able to fiddle with the tuning once he gets the engine back into the boat and he's wary of multiple carbs and fuel injection ! Oh well ...
The 4-bbl manifold looks like the obvious choice here. Now I have to find a supplier for the manifold and a supplier for a non secondary 4-bbl carb ... one thing leads to another.

tirebiter@compuserve.com

Now I have to find a supplier

I see that a regular on the boards ktbundy has put some new parts on e-bay last night, so you might check there if the price is right. He has a clifford 4-barrel intake, headers, windage tray, and a nice looking cylinder head all up for auction. Just do a search in e-bay motors for "slant six" and they all should show up.

-D.Idiot


res0aus2@verizon.net

snip

Now I have to find a supplier

Why a non secondary? [which I take to mean
non-progressive].
Dave


dbrode@hereintown.net