For reasons that still escape me, I picked up a factory 2x4 Cad intake. So naturally, now I'm thinking about things... I went through about 10 pages of the search for Cad 390, and I've got a couple questions I hope some of you Cad gurus can help me out with. Cams: one post said a stock '60 tri-power cam was pretty good. Does anyone make decent cams for these engines? And if the stocker is good, are the suppliers using new blanks, or regrinding old cams? Roller blanks: from what a few people said, SBC lifters are the right size... so I'm wondering if SBC roller lifters would work, and if they will, is anyone making a roller cam? This would go back to the above question. I read one old post that said the stock 2x4 intake isn't a great performer. But that's what I'll be starting with if I go down this road. Has anyone actually done any testing on which intakes are good and which ****? Compression: are there any decent pistons out there that aren't full-skirt and have a 10:1 compression ratio? Or close to it? There's no reason to go with '50s-tech full-skirt pistons, so I'm thinking a more modern design with a shorter skirt and 9.5-10.0:1 compression would make some decent power. Rockers: I've read that Stude adjustable rockers will work, and are a faster ratio when installed on the Cad. Can anyone give me a little more specifics? Valve Covers: I saw a link to Hildebrant valve covers that are being reproduced. Anyone know if those are still in business? They've got the dimples in them to clear adjustable rockers--are dimpled covers required to clear adjustable rockers? From what I understand, the 331, 365 and 390 will basically interchange. If I'm starting from the beginning, I can't really see a reason to start with anything smaller than 390. What should I be on the lookout for? Heads: will 390 heads take bigger valves? Can anyone ball-park what they think a 390 with good valves, mildly ported heads, a good cam with the faster lifters, 10:1 compression and that 2x4 intake will make? I know that's a broad question, but that's what bench racing is all about! -Brad
Did you find the thread by Cadillacin Marcus? It's ***led Tech Info: Cadillac OHV V8's 1949-1962. There is alot of good info in it.
I'm pretty sure the 390's are 10:1 compression or so stock. I have a '62 390 and thats what it is..Yes you need the dimples to clear the stude rockers. But the stude rockers slide right onto the caddy shaft. Isky makes performance cams for caddy, I'm sure a couple other do if you call and talk to em. Sometimes the older stuff isnt on their websites. I'm sure others will chime in with some more..
I've got a '58 Motor's Manual I'll quote you some numbers for a '58 365 10.25 compression ratio 310 HP @ 4800rpm 405 ft. lbs @ 3100rpm 3 carb 10.25 CR 335 hp @ 4800 405 ft lbs @ 3100 I've got a '60 coupe deville 390 and I was told it was 10.5 CR This book also has the cam specs but I don't see a different cam for the 3 carb motor so I don't know if they would have had a different one for '60
Here's a great start...my website! Copy of Marcus's post from Here: http://hotrodcaddy.com/?p=17 331/365/390 Speed part gallery: http://www.hotrodcaddy.com/speed_parts.htm Hot Rod Deluxe Cadillac 390 Article: http://hotrodcaddy.com/?p=139 Also, tech specs of 1950's Cadillac engines: http://www.carnut.com/specs/gen/cad50.html Tech specs of 1960's Cadillac engines: http://www.carnut.com/specs/gen/cad60.html I wish this info was so easy to get when I started looking into 331/365/390's.
Lots of good info here: http://www.modifiedcadillac.org/forum/index.php http://cadillacmisfits.com/index.php http://www.cadillaclasalleclub.org/ Gary
I'll address these as I can one at a time in case you need more input than you've already got. the deal with cams is that for major grinds you've really got to be racing. I had a mild custom grind on mine to give it a little lick, but stout grinds are only good for winding it up-- and are you really going to be running 6000 rpms that often. isky makes a cam and lifter kit and there's some folks out there still grinding. Marcus put me in touch with the guy that did mine I think he's in utah. I went mild--these things have a ton of torque anyway. SBC lifters work as will the vales (1.94 and 2.02, but you have to use the stude adjustable rockers with them and shim out the valve covers) the big drawback to the factory 2 x 4 (other than weight) is that it's designed to run 2 barrels from each carb all the time--not a progressive feed. you have 4 barrels running or 8 otherwise you have issues of fuel getting to cylinders (I can't confirm this personally, just what I've been told--I ended up selling my 2x4 and using a 3 x2 instead). the standard 4bbl is a good perfomer for ease of installation and function. early 50's stude v-8. sorry don't recall years right offhand. not sure about repop hildebrant valve covers, but offy is making them and you can get them through speedway with adjustable valvtrain you'll need a spacer, though. you want 390 heads--see comments above the 331, 365 and 390 are very similar. 331 and early 365 have the caste in bell housing, the late 365 and 390 it's separate. heads, intakes etc will interchange. If you've got a 390 it's your best bet. better oiling system. inside I can say from experience that 365 and 390 have different pistons. the 390 pistons are shorter to compensate for the extended stroke (by the way if anyone needs a new set of 365 .030 pistons I've got them along with all the rest of the guts to stroke a 331) to ball park your bench question I'll say that the factory 365 with 2 x4 ran like 325 hp (or was it 340--that may have been the 3 x 2 390 in 60 --don't have my books in front of me) from the factory you can guestimate from there. haven't had a opportunity to get my on a dyno to see, but I like the performance. all the best man
There are a number of different "factory" dual quad intakes; some perform better than others. Try this list: http://www.thecarburetorshop.com/Multiplecarbmanifolds.htm Jon.
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