"Freshening up" a 45k 500...suggestions?

Discussion in 'Big Block Cadillacs' started by airbrushguy, Jul 15, 2019.

  1. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
    1976 eldorado
    New to the Forum......

    I am restoring/modifying a 1949 Hudson sedan and among other things, I am putting a 1976 Cadillac 500 engine and TH400 trans.
    I am planning on installing an Edelbrock aluminum manifold, Holley 780 Carb, headers and new timing chain, oil pump, and adding a rear sump Eldorado oil pan. The 1976 engine is from a 45,000 mile Deville and I would like to leave it relatively stock except for the afore mentioned additions. It appears very clean and undamaged from above and below.
    If there won't be much advantage, then I won't do it, however, if the MTS #5 cam would be a significant improvement, then I'm interested....
    I have "opened up" this very clean 45,000 mile engine and the cylinders are clean, no ridge or scores, bearings look good and I have had the heads cleaned , new seals and springs checked....all good. I really wanted to only drop the engine in the hudson as it was in the Cadillac but when I heard about the plastic coating on the timing gear, I went a little further. I am going to replace the timing chain, oil pump, water pump and fuel pump, new gaskets, Edelbrock manifold, carb ( would like to use a Holley just because I have had better success with them and never liked Quadrajets especially smog era), I will not be using the smog pump etc.
    I am planning on using the car for actual long trips in my retirement and felt that maybe the stock performance of a '76 car with low compression would be a little disappointing around town. I would like to install roller rockers to compensate for the stock setup which appears to be a weak link. Not familiar with the correct setup, adjustable/non adjustable ( https://www.ebay.com/itm/Cadillac-4...418&pg=2060778&_trksid=p2060778.c100290.m3507 )
    I would like to keep costs down wherever reasonable.
    I am planning on using a Chevy S10 rear with either a 3.08 or 3.42 gear ratio.
    If anyone has used a specific cam that they feel would be worth installing for my particular purposes, please suggest.
    My main goal is a reliable refreshened 500 with TH400.

    Please let me know your thoughts on this.
    Thank you
     
    Last edited by a moderator: Jul 15, 2019
  2. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
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    No suggestions?
     
  3. robocop

    robocop Member

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    What vehicle(s) do you drive?:
    1987 Cutlass Supreme 2 door with 500 Cad/Turbo 40
    I'm using the MT10 with the stock rocker system. It has seen 5000 rpm many times and still no problems. I had the original Ts and also I have used new reproduction Ts.
    For the MT5 the stock system is fine. You might have to buy new pushrods to adjust length to get good preload and reduce valvetrain noise.
    I would do a valve job, replace the springs with ones recommended with the cam. I would get a good oil pump not stock replacement. Stock pump supplies only 35lbs at cruise and a lot less at idle. The Edelbrock intake is very expensive and supplies not much more hp than stock; it does save a lot of weight. If you still have the stock air pump setup, get rid of it and buy the air pump elimination pulley set. Recurve the distributor. Copy the advance curve of a musclecar from the 60s that had auto trans. Replace the timing chain of course. Zero deck the block. If you are going to long distance tour the car by all means get the 3.08 rear.
     
  4. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
    1976 eldorado
    Could you suggest a specific oil pump?
     
  5. Caddylackn

    Caddylackn Member

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  6. 50olds

    50olds Member

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    What vehicle(s) do you drive?:
    50' olds
    Welcome! Cool! I'm building my Cad mill for a 50' olds. Love to see a pic of the car..

    Julius (who is banned from the forum but a very knowledgeable well known caddy guy) claims the stock cams in later years are pretty good just retarded a lot (think he said 11-15*?!) for emissions. If you're going to replace the timing set anyways and not looking for a big cam, I think you'd find the stock cam specs are very close to the MT5 just not with the same timing built in. It might save you a lot of $$ to research that. The street true roller set allows you to advance or retard the cam 4*. I think if you were to set it up an entire tooth advanced on the 4* retard it would get the cam almost "straight up" by performance standards.

    Oil pump look into the "G" (gm g body) style pump. It puts the oil filter at a less awkward angle and makes for more room with a swap. You can also shim the bypass spring and a few other things to increase oil pressure. Melling makes the 58G pump in cast iron which is the go-to pump for most people. Don't fall for the gimmick of "high perf" or "high volume" Cadillac pump, there is no such thing. Blueprinted just means spec'd and smoothed castings.

    You can also save some cash by using a mid-sump pan and pickup off a 425 or 368. If your hudson is set up like the olds it will clear but be very tight. They are less desirable than an eldo pan and more available.

    Definitely the next thing not on your list for upgrades would be a set of rockers. I actually adapted ls rockers onto mine but haven't tested them yet and it wasn't a simple task.

    Also if you're deleting the smog pump the 425 has a much better pulley setup. And a better single plane intake if you want to save the cash spent on an Edelbrock. AND that G body pump. So its worth looking for a 425 for parts for a swap imo.

    long trips you'll want a 3.00 gear maybe even something in the 2's. Or find a 200-4r o.d. trans to build up. They are not as strong as a 400 but can be made to handle the torque I believe.

    -Joel
     
  7. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
    1976 eldorado
    Just to clear up my situation....the engine has 45k miles and when inspected looks in pretty good shape( i.e. cylinder walls, main bearings etc)
    I have bought the roller rockers already, as well as an Edelbrock intake, a Cloyes timing set, telling oil pump, an Eldorado rear sump oil pan and pickup. I am not sure what I will use for a carb, but I do have a perfectly good Holley 780 w/auto choke...??
    I am tempted to put in a mild cam, but that's the old hotrodder in me talking, I really only want a very reliable cruiser.
    My father had Cadillacs back in the '60s and '70s and my memory seems like their performance was fine for this project.
    Repeating.....reliability is my main factor, I don't want to be stranded midway on a cross-country cruise.

    Your suggestions have been helpful and any others are more than welcome.
    Thank you
     
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  8. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
    1976 eldorado
    Would I really want less than 3.08? My buddies who had 3.08s in their chives back in the '60s had very slow cars that only came on up top-end?
    I can get a 2.74 rear but wasn't considering it.....should I?
     
  9. Cadillac Kid 1

    Cadillac Kid 1 Well-Known Member

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    These motors were intended to have a top speed of around 4500RPM with a flat torque curve that starts at 1500 RPM. Unless you intend to do some racing this motor in your 3500 pound car with a 3.08 rear end will be lively.
    Greg Surfas
     
  10. 50olds

    50olds Member

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    Even with 3.08 gears you are going to have some high rpm's on the highway to cruise 70-80. When I saw you mentioned long trips that is why I recommended overdrive, or the deepest rear gear available. You'll do better on mileage too.
     
  11. Darius

    Darius Well-Known Member SUPPORTING MEMBER

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    Really, in as much as you already have the roller rockers, along with the Edelbrock intake, I would not hesitate in the least going with the MTS 15 (Old design - no idea of what the NEW YOKELS are offering) ... OR a similar camshaft from the Boys in New Mexico. On another post I asked the weight of a 1949 Hudson but nobody responded. After looking it up for myself (what a concept) it is clear that any of the various models available in 1049 are going to be AT LEAST 1,000 pounds lighter than the Cadillac your engine came out of. In other words, you can easily go somewhat more performance oriented with your camshaft specs, and due to the More Than Sufficient Torque of the Caddy engine not in any way over-cam your ride. These ARE NOT small block Chevys, or even big block Chevys.

    "reference weights: shipping weight 1656 kg / 3650 lbs base curb weight: 1735 kg / 3825 lbs "

    https://www.automobile-catalog.com/...odore_series_494_eight_4-door_sedan/1949.html

    You have already ponied up for the parts that will give you peace of mind as to reliability; and the torque of the Caddy is second to none, therefore the door is open for you to add a little pizzazz to your camshaft selection.

    For what it's worth, my 3300 pound (guesstimate) Caddy powered Studebaker was built with 3:08 gears, front and rear (AWD). Combined with the 0.75 overdrive of the 4L80 will give me a 2.34 "down the road" cruise.
    I'd stick with 3:08 for your application and call it good.

    bro. d
     
  12. airbrushguy

    airbrushguy Member

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    What vehicle(s) do you drive?:
    1976 eldorado
    According to the spec sheet (below)on MTS 15, it sounds like it's more cam than I want for (a little peppier) reliable cruiser. Remember, I'm starting with a low compression 1976 500.
    Thanks for responding


    RPM bands on this camshaft can exceed the boundary of safety for engines with stock connecting rods. Forged “H” or "I" beam connecting rods are preferred. If you want durability, aftermarket rocker assemblies are also required at this level of power and ported heads are strongly recommended to facilitate the build. If you’re going to pump up your motor, you really need to make sure all of the components in your build can hold up to and help promote the performance of the cam and to keep your engine in one piece. The CHP #15-th Cam cams works best with a 3.23 to 3.73 rear gear ratios. For extra measure, toss in a 2,000 RPM Torque Converter ---- and be prepared to be pinned into the back of your seat.
     
  13. robocop

    robocop Member

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    What vehicle(s) do you drive?:
    1987 Cutlass Supreme 2 door with 500 Cad/Turbo 40
    I ran a 3.08 in my 500 powered 87 Cutlass. Performance at all speeds was very good but it revved at like 3000 rpm on the highway at 75-80 mph.
    I swapped in 2.73 rear gears and it made the car a little softer in the acceleration department. Wish I'd left it alone.
     
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  14. Darius

    Darius Well-Known Member SUPPORTING MEMBER

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    An interesting thing happened to me on the way of developing my attitudes about camshafts for the Caddy 500. My views changed.

    I'm am not a proponent of high RPM big block engines, favoring instead the inherent torque that comes from massive cubic inches. Previously I went for conservative cam specs. Any goals for higher horsepower and torque could come through forced induction, in my case turbochargers. As a result my first Caddy build utilized a reground camshaft, stock rockers and cast pistons. The result was a SUB- 8 to 1 compression ratio and a mismatched camshaft -which I had intentionally installed retarded. That engine was placed in a mid-sized 1979 (?) Olds Toronado with a 425 Turbo-hydro transaxle fitted with 2.73 gears. I had done about everything wrong if the goal was snappy performance; but those cubes, in a mid-weight car, pulled me through. In hindsight my satisfaction would have been greater had the choices been different. That led to my second Caddy build.

    The point of my rant is that you appear overly cautious due to marketing hype!! Certainly the vendors want to sell you everything in their inventory and therefore ramp up what "you must have." The roller rockers you've already purchased are the most critical part of your engine not busting its guts at say a top of 5000 RPM. All of that other verbiage about is marketing.

    I don't mean to dismiss your points. They are understood. Still, I hate to see you leave too much fun on the table due to hype.

    Best,

    bro. d
     
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  15. 5one9

    5one9 Active Member

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    You'll be happy between 220 and 230 degrees at 0.050". That's a big engine you have and 220 is very drivable even in a 'small' 350 Chevy.
     
  16. Bruce Roe

    Bruce Roe Member

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    If you are spending time on the road, put in a 2.41 axle and a SWITCH PITCH
    electronically controlled trans. That setup in my 77 Olds (4150 lb) with stock
    mild mannered 403 (but duals) does 91 mph in the quarter mile, 0-60 in 7.5
    second, 19 mpg at 70 mph. Just over 2000 rpm at 60 mph. Use a 500 and
    expect a lot more performance, esp if the car is lighter. Mileage, well a lot
    better than a 3.08:1 axle. good luck, Bruce Roe
     

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