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Cadillac 331 engine build help

Discussion in 'The Hokey Ass Message Board' started by 49CadiClubCoupe, Jul 19, 2011.

  1. Hi everyone

    Once again I turn to the wise minds of the HAMB for help - I would be lost without your help.

    Ok, so here is the rub - I am in the process of rebuilding my '49 Club Coupe Cadillac and am hoping to start squirreling away bits and pieces for the engine build as I see them come up.

    I have the original engine for my car and am hoping to go for a mild custom vibe. I am after extra power from the engine but not looking to go over board. I have read some excellent posts on here and seached a lot to get some good info. Most of what I have read unfortunately does not answer all my questions.

    Everyone suggests adding 390 heads, however I would like to keep my original valve covers but have read this will not be possible with the 390 heads. If I put 365 heads on will the original valve covers still fit? Or can you go 390 heads, adjustable rockers and double gaskets or shims to use the original valve covers? Are the bolt holes in the same spot?

    I understand that I will need to fit adjustable rockers if I fit the 390 heads, again if I go with the 365 heads and fit adjustable rockers can I retain my original valve covers?

    Is going with the 365 heads a good option or will the gains be minimal?

    I am looking at either a double or triple carb set up on an Offenhauser intake for the top. This may be opening a can of worms but do you go 94's or 97's or it doesnt matter? Do I need to find a matched set or can you just buy three and a linkage kit and get it running? Is a triple set up overkill for a cruiser spec motor?

    Thanks!!!!:D
     
  2. Can I bump this for the US crowd, lots of lookers no replies - would be grateful for the advice!
     
  3. 40StudeDude
    Joined: Sep 19, 2002
    Posts: 9,456

    40StudeDude
    Member

    Personally, it's all about choice.

    Would I do three carbs on any engine...??? No, past experience reveals too many problems with them in normal everyday traffic...I wouldn't even put two fours on an engine...but then again, I wouldn't put a bigger cam in nor would I use big bore pistons...s-t-o-c-k, from the factory is the only way to go IF you want a hiway cruiser. The factory engineers knew an engine would last longer without any mods.

    To answer your questions as to different heads, I've heard 365 heads will breathe better on a 331"... but I don't know about the valve covers.

    Would I use the stock 331"...? No, I'd find a later model Caddy engine...parts are more accessible, and prolly reasonable, maybe not where you live. I used a 500" in my '55...instead of using the stock 331"...more power and (hopefully) better gas mileage.

    If you want to see my '55 Cadillac build, go here:
    http://www.jalopyjournal.com/forum/showthread.php?t=329070&highlight=the+best+55+caddy+build

    There's about 36 pages there so be prepared to spend some time.

    Good luck with your Caddy...my '48 coop is waiting in the wings right now.

    R-

    PS, I clicked on your link...couldn't read much of it...white type on a black background is hard on these old eyes...and the type is way too skinny to read...

    R-
     
  4. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    My grandpa had a new Caddy in 1950. It had a hydromatic and a two barrel carb, it was one of the faster cars on the road at the time. I have no idea what fuel mileage it got, he was a Standard Oil dealer, so he wasnt concerned. I would go with a stock rebuild and maybe a later model small four barrel intake.
     

  5. F&J
    Joined: Apr 5, 2007
    Posts: 13,223

    F&J
    Member

    IMO, bigger heads are for very high RPM, you don't sound like you need that.

    Keep it simple. I happen to like real genuine tri-power carbs, run with progressive linkage. Trouble free if you set them up right from the start. I would not try to use regular 2 barrel carbs.

    If it has a 2 barrel, then yes, going to a 4 barrel is also good.

    A very light cut on the heads to bump the C/R just a bit. That should help on mileage and power if you don't overdo it.

    If you do a cam, keep it a mild hyd. Just my opinions.
     
  6. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    With the exception of very early '49 engines, which had valve covers that were retained by two bolts through the center like a '49-'58 Olds, all of the covers will work on all '49-'62 cylinder heads. Whether or not you can use aftermarket adjustable rocker arms without interference will depend on the rocker design; some had the adjusting screw sticking out the top, some out the bottom. All engines through '54 had the same bolt pattern on the rear as your stock block, but in '55, they changed the rear of the block for use with a fully detatchable bell housing. Someone made an aluminum adapter in the late '50s/early '60s that allowed the use of '49-'54 bell housings on '55-'62 blocks----I wish that someone would reproduce it now; I've got to believe they'd have no problem selling them. I don't know why you'd need adjustable rockers just because you bolted later heads on your engine, though.
     
  7. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    Also, as far as hotter camshafts go, the later stock cams ('57-'62) were considerably livelier than your '49 cam and would be a low cost upgrade for you.
     
  8. F&J
    Joined: Apr 5, 2007
    Posts: 13,223

    F&J
    Member

    I had one, I have pics somewhere on hamb, but..

    I was wondering if that could be used to put the early A/T on the 55-up engine?
     
  9. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    I don't see why not; all it did was convert the later engine to the early engine.
     
  10. r8odecay
    Joined: Nov 8, 2006
    Posts: 787

    r8odecay
    Member

    Take a look at the 4" pistons offered by Falcon Global. I ordered a stock 331 piston from Kanter, and it was JUNK. Then I decided to bore to 4", bought the Falcon pistons and they were simply beautiful. Look like Wiseco's and fit and weight true. Not affiliated with them at all, just relaying a positive experience.

    My build is very similar to what you are describing, 365 bore, 390 heads, Isky Torque cam, early valve covers, and has been pretty straight forward so far...
     
  11. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,150

    d2_willys
    Member
    from Kansas

    All you need is a 55 a/t bellhousing and you are half way there! You, of course will need to drill the crank out for a pilot bushing and have the flywheel counterbalanced if the later engines are externally balanced.

    You may need a 55 starter, flywheel, and torus members.

    The adapter being mentioned is much like the front bellhousing used on Pontiacs, but it (Pontiac) has a different bolt pattern than Cadillacs from 55-62.
     
  12. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,150

    d2_willys
    Member
    from Kansas

    As for building a 331, may I suggest 1955 331 heads, and probably manifold. 1955 Cadillac improved vastly on the head design and called them "TURBULENT WEDGE" heads. Funny how the HP went from 230 in '54 to 270 in '55. A lot of it may have come from the better breathing heads. I am sure they increased the CR a little too. Any way you look at it 1955 331's and their parts are the way to go.
     
  13. Now this is why I love the HAMB - Thanks one and all for your input!

    Thanks 40studedude, I have spent a lot of time looking at you build - amazing and inspirational. I would like to keep the 331 as it is original, I cant wait to see what you do with your '48 and I will tweak the font and size on my website :)

    F&J, I was under the impression that the 365/390 heads were the go as the 331 heads don't flow too well. I have been told its hard to run fast if you cant breathe properly!

    Thanks Heathen, a new cam is definitely on the cards and my covers are bolted on the side. My car was built in March '49 early, still waiting to confirm which cam it has in it - spring or not.

    Thanks MTABike, looks like the adjustable rockers are not necessary and I saw that set up. Looked great however being in Australia I was concerned about freighting it here. The freight could be half my build budget!! I know exactly what you mean about comparing your and your friends cars,...I just want a bit more than stock 160hp.

    Thanks r8odecay, I had seen the Falcon gear and wondered what the quality was like,..not something you want to take a punt with!

    Lastly, thanks d2 willys, some good advice there. My '49 put out 160HP, I would be happy with 230HP!

    Seems like I was over complicating things and can achieve what I am looking for a lot easier. Thanks
     
  14. F&J
    Joined: Apr 5, 2007
    Posts: 13,223

    F&J
    Member


    Here is the cad adapter bell I once had; this one came with the stock early cad bell for the "Cad/LaSalle" 3 speed stick trans

    The guy I got it from said some hotrodders told him is was for putting a ford trans on a SBC:confused::D
     

    Attached Files:

  15. HoldFast
    Joined: Jan 24, 2005
    Posts: 816

    HoldFast
    Member

    Personally... I'd do a nice clean stock rebuild on that motor with some pretty bits if you're in to that.

    If you want performance get a newer cad motor in there. Even a 365 would be a huge upgrade...

    Just for reference, your 49 came from the factory with 160hp. My 53 had 210 or 220 depending on who you ask... a 58 365 which is what I would probably run, came with 335hp from the factory.

    It's gonna take a LOT of money to come anywhere near that number with your stock motor.


    So my advice stands. Build a nice clean runner and enjoy it. You start putting multi carb set ups on there you instantly become less reliable, you'll have more parts to replace and you're looking at $1500 to do it right.

    That motor is gonna be under a huge hood and be rarely seen.

    Spend the $2500 you're realistically looking at for goodies and hop ups on a new motor you can take your time with and go crazy. Or spend it on suspension, tires, interior, paint... whatever else your car needs.
     
  16. Thanks HoldFast, appreciate the comments. I definitely like the pretty bits, (one of the reason I like double or triple carb's) so want it all to look good

    I really want to keep the original motor in the car as my car is all original and I would like to respect that and keep it that way. Some guys wouldnt care and thats fine, its just not me. I would be happy with 200-220hp.

    I have definitely scaled back my original thoughts for the motor and agree that spending the money elsewhere on the car makes a lot more sense.

    Cheers
     
  17. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    I would think that a 4 bbl setup from a '52-'55 engine, dual exhausts, and a .060 shave off of the heads would give you enough of a boost to keep you out of the ditch.
     
  18. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,150

    d2_willys
    Member
    from Kansas

    Like I said, I would investigate the 55 heads! Better breathing for the 4bbl setup. Mild cam, dual exhausts, = 230hp+
     
  19. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 1,282

    Barrelnose pickup
    ALLIANCE MEMBER

    I have a early 49 331,the first with the 2 centre bolt rocker covers and the spring loaded cam but after asking lots of questions I am now building up a 58 365 to go in a 30 coupe I'm putting together.I like the idea of the 49 but dollar wise.
    As said by a few theres alot more bang for your buck in the 365.I scored some .030" over pistons and all the gear I needed from Falcon plus a Esky hyd supercam and I should end up with realiable street mtr,and costing alot less than trying to perk up the 331. A very mild 365 in an A will give me enough jollies.I will leave the 4 barrel intake on to start with to run in then see what happens.
    Good luck either way.
     
  20. Thanks everyone once again,...Looks like I will need to come up with another project to do a bigger Caddy motor in!

    Thanks heathen and d2 willys (you are very persuasive :) )I saw something on here recently listing all the head cc's of Caddy heads by years,..just searched for it but couldnt find it again!

    Barrelnose, that 365 in the coupe will definitely give you some jollies - sounds fun! Did you get the Falcon gear local or did you bring it in yourself?

    Anyways,..I think I have figured out which way I am going to go,...stay tuned for the build update down the road. Many thanks
     
  21. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 1,282

    Barrelnose pickup
    ALLIANCE MEMBER

    Cam,I just read your blog,good read mate regarding how you came across the car.
    I bought in all the motor gear myself as theres nothing available locally over here anyway.
    Falcon shipped quickly,one small hitch but rectified it straight away,pleasure to deal with.
    All the gear supplied appears okay,hard to compare without dealing elsewhere.

    Chris
     
  22. Thanks Chris, I appreciate your comments on my blog. Time to get busy so I can post some more on there! I enjoy the writing side almost as much as the building!

    Thanks also for the Falcon feedback,... good that it was a simple process. Looks like I have found a supplier for my stuff.

    Cheers

    Cam
     
  23. inlineNmine
    Joined: Oct 3, 2011
    Posts: 19

    inlineNmine
    Member

    Chief012, your just like me. I look it to look nice when its all done, but i like it to be all original. My 54 Cadillac has its original 331 4 barrel, and hydramatic, and that was the only way I was going to go. The motor wasn't too pricey to have it machined. I did the rebuild so that kept the costs down. I am proud of my 220 horses, and prouder to have a numbers matching original 54 Cadillac. Like you said, to some it doesn't matter, but to me, i like them how they were. Go ahead with the 331
     
  24. 40StudeDude
    Joined: Sep 19, 2002
    Posts: 9,456

    40StudeDude
    Member


    FWIW to you and Chief012...we rebuilt my brother's stock 331"/Hydramatic in his '54 hardtop about three years ago...this past summer we did a lot of out-of-town rod running (read that lotsa miles)...and I'm sad to say, my brother's stock rebuilt 331" Caddy engine was getting 20-21 mpg...of course, he's not sad -I AM...cuz my big inch 500 Caddy could only muster 14-16 tops...

    But it's got lots of scoot...we did the Omaha to Denver trip (600 miles) in 7 1/2 hours in September...and that's not bad for a couple of guys that are both over 65...

    R-
     
  25. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 1,282

    Barrelnose pickup
    ALLIANCE MEMBER

    To give credit where it is due I finally have my 58 365 heads under way(same castings and valves as 390) only to find Falcon had supplied
    the wrong inlet/exhaust valves with the kit I purchased nearly 2 yr ago.
    I emailed them 2 nights ago about it and they have already sent out the correct set,apologised for the mistake and will credit the cost of returning the others back to them.What can I say except great to deal with and that is refreshing in todays markets.And yes,it all appears to be quality gear.
    Chris
     

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