Tech Info: Cadillac OHV V8's 1949-1962

Anyone?

 

2.02 Valves will require offset guides if I remember correctly.Not really needed unless you are trying to squeeze every bit you can from this engine.1.94's work just as well and go in a lot easier.Yes you should leave the stock center two valves to balance it out nicely.

 

I installed new stock guides and personally cut my 390 heads heads for 2.02 and 1.6 valves and they fit fine. The late 390 Cadillac heads rock!! They have very nice ports stock and if you compare them to chevy or ford heads the hold WAY better tolerences. After I installed the 2.02 and 1.6 valves i pocket poted them, and I took half the time and metal from the head....

 

Interesting..Thanks for the info!

 

Thanks for the help guys,getting this 365 together is a big learning curve.
Just fitting a flywheel,clutch and torino toploader up to a spare block I have to get the spacing and the fitting right.Turns out it's a 59 390 so it has me thinking of up grading from the 365.I also have the crank and heads for it.The rocker gear appears to be the same as the 58 365.

 

Thanks to help from the Cadillac collectors, the year of my engine has been found. There is a serial number stamped on a flat surface at the front of the block where the passenger-side head meets the block. The first two numbers represent the year (53 = 1953 in my case).

 

Don't know if it's common knowledge but it appears that the 58 365 pistons are the same as the 59-62 390 pistons,just found this out last night from the Egge site.That means the pin height must also be the same.As mentioned before the blocks and heads share the same casting #s
The only difference then must be the crank and valve sizes and of course the upgraded oil filtration system.
I thought I would put this out there for correction or comments.
Cheers still learning.

 

not sure about the 58 specific, but the 57 365 are different from the 390. I bought a set of non-year specific "365's" piston when I built my 57 motor (second hand on the auction site a decade ago). I stroked it with a 59 390 crank and had to buy 390 specific pistons because they would not work--fortunatly the engine builder noticed it during the assembly.

 

Yeah,the 57 365 has different part #s for the pistons.
What else did you have to do to the 57 when you stoked it?
I asked this on another thread but no answers yet.I was asking about stroking a 58 365 but would be interested to know anyway.
Thanks

 

It is my understanding that a 390 crank will not fit in a 365 or 331 without extensive machining. Is that wrong?

 

yes that's wrong--I guess. I dropped the 365 block off at the napa machine shop in Ames Iowa with the guts from the 390 (crank included) and the engine guy there (mark) did the rest. he called and told me the pistons I had wouldn't work and showed me why so i ordered new one's from kanter. there shouldn't be a difference--the early 390 block is just a stroked 365 before the change to the spin on filter oiling system.

I talked to Marcus LOTS before I did the build. I'm running a 57 365 (factory 2 x 4 motor). heads were built with hardened seats and 1.94 and 2.02 valves. ordered a custom grind cam from the guy marcus reccomended in utah. basically he had two grinds--mild and wild--would never have seen any benenfit from the wild--didn't kick in until like 5000 rpm--and I mostly highway drive. block was bored .030 for the afore mentioned pistons, crank was ground .o10 (i think) and everthing honed. didn't spend the extra $250 to get it fully blue printed but it's been a good motor. rebuilt oil and water pumps, petronics kit. runs like a top. have a little more blow by than I'd like given the low miles and gauge shows what I'd conider low oil pressure, but never any problems and no complaints frome me. at goodguys charlotte I ran out of the back stretch of the speedway before I ran out of 3rd gear.

I guess that's the long way of saying "to my knowlege not much had to be done". just standard rebuild stuff. just make sure you've got 390 pistons and crank.

 

Cheers for that,I just had a call from the machine shop and my block needs at least one sleeve but you can't be to choosy down here.
A mate just bought it up last night that if the piston,rods and block are the same for 58-59(all the same #s) then where is the extra 1/4" of stroke taken up.Going to check the block deck heights on both blocks tonight.Got this far I may as well carry on and stoke the 365 out.

 

That there is good info! Thanks. I'm not ready to do my 331 yet, but I do have a whole 390 for spares. I want to keep the 331 for the "old school" factor. If it isn't obvious from the outside, why not? The 331 has very thick walls so it shouldn't be any problem overboring to the stock 390 bore. If the crank fits right in everything is golden.

I'm still using the 331 for mock up, so I don't want to tear into it yet. Besides, I need to limit myself to 27 things at a time. One more project and I'll become inefficient.

 

Either the rods are shorter or the pistons are different. No other explanation!

 

As long as your 390 is 59-62 it apparently should be okay,They changed in 63 I believe.If I'm wrong someone may chime in.

 

Measured up the blocks,rods and pistons tonight and it's all in the rods.
The 59 rods are shorter by roughly .160". I had to go thru the process to understand
this for myself.Probably common knowledge to those in the know.
This is only comparing a 58 365 to a 59 390.

 

Can anyone please tell me if these #s are an early or late 57 365 block.
Stamped #s not cast 5762051864.
Any help would be appreciated,Thanks

 

I'm really looking forward to the reply on this also. I have a 58 block at the machine shop right now and do not know if it's an early or late block. Some engine kits say there's a difference between early and late 58 caddy engines. Anyone know the difference??

 

There seems to be a difference in the lifters and pushrods,working on part #s in kits anyway.Hopefully someone will chime in.I just brought a couple of motor books so when I get them hopefully theres some info in them about this.

 

I got a 390 at the machine shop and the guy called me to ask how thick the heads are since he needs to boss the area for the valve springs to fit in? I got a custom grind cam and matching springs for it. Someone noted using chevy z 28 springs? What year and motor, 350? G.

 

Visited the engine shop today and learned a few things....

What I know:

390 crank will not drop into a 331 block without modification. The 390 mains need to be ground down to the 331's diameter

331 rods are wider than a 390's, but they use the same bearings (the 331 rods overlap the bearings)- the 390's rod journals are narrower

331 rods are longer than 390 rods, but the all-knowing shop reference guides (both of them we looked at) had incorrect info showing the 390 rods to be longer. The guides also seem to have the compression heights wrong on the pistons.

The compression heights are different between the 331 & 390 pistons

My block sonic checked with a minimum wall thickness of .31, plenty of material to go to a 4.00" bore

What I need to know:

Does anyone know the deck height on the 331/365/390 block?

 

331/365/390 deck height (crank centerline to the bock surface that the head bolts to) = 10.560" (measured)

By comparison a late 390 (and presumably the same as a 429) measured in at 10.114"

These measurements were of actual blocks using a 12" dial caliper so are only approximate (+\- .010"). It is also unknown if either block had been decked.

Measured piston compression heights:

331 = 2.010"
Early 390 = 2.095"

I measured my early 390 rod and it came in at 6.500"

So the (modified) 390 crank in my 331 block with 390 pistons and rods should leave me about .0275" deck clearance which is pretty good.

 

Turns out my 390 heads have 66 cc chambers.

 

I had problems with the original Delco distributor on my 331, especially when I got the compression and revs up. The after market cap and rotor were crap, and caused mis fire at revs. There is a Mallory Ford (OHV) dizz that is easily adaptable to the Cad block, which works well. I can retrieve the details if anyone interested. Took less than an hour to machine the housing and drive shaft down. Does need a lathe. Tom.

 

Funny you're saying that because I do have one brand new sitting in a box and was thinking of adapting it to my 390 after comparing sizes.
By the way somebody asked what year of Z28 valve spring was used in the Cad but nobody answered, I'd like to know too.

 

I have a set of Studebaker rockers that is also suppose to be a plus for the Cad 390 rocker assembly on the Cad shafts. I have ben told they have a higher lift anyone know? Also on the road draft tube why not just put a vent in the valley pan?

 

I don't think that they have a higher lift (If I recall they have the same length), they'll require custom length push rods because of the different height on their back side, the real advantage is that they are adjustable.

 

Does anyone know if a breather on the valley pan would work to replace the road draft tube?

 

yes it would

 

Has anyone had problems with getting new rocker shafts for their 365-390 cad motors or am I the only one measuring them?
I have bought 2 pr from 2 different suppliers and both sets have been ground .003" under size.Obviously they have got their parts from the same supplier.
.003" under takes the shafts to the worn specs and makes the shafts loose in the rocker posts let alone on the rockers themselves.
Are there any good shafts available?At least in spec ones?