440 Cam Choices

[Schober Motorsports]

I'm going to be rebuilding a 440 out of a motorhome for my 67 Coronet and I really want to put a good size cam in it. Its the 452 heads so I know I got those going for me. I'm planning on having them milled to bump up the compression. Also I wanted to know because I really couldn't find a definite answer, whats really the biggest cam I can have with the stock springs? I mean some people have told me .488 lift is pushing it while some say that with something close to the .509 cam I can make it work...

Also how can I figure out what else I should be running with it, like what would be a good combination?

Thanks!

 

[godfatherofchry]

the first thing you should do is get rid of the stock springs...BUT everything else I have run with no trouble my first motor was a motor like this a hi vol oil pump oil restrictors to the head a 509 cam kit. torker intake 780 carb.3800 converter shift kit in trans and 456 gears in a 73 duster.and ran 11.50s and drove it everywhere.I also milled the heads 75000ths.you will have to mill intake to for that much.and you might have to shim the rockers.....it worked for me..back in the 80s. i think I had a total of 450 bucks in that motor and beat the hell out of it. for two yr. O and I had 3000ths.clearance in the crank rods and mains and ran 50wt.Kendell oil.I never did blow this motor...Artie

 

[Meep-Meep]

Chances are the motor home engine will not have enough compression - even if you mill the heads - to support any kind of hot cam. The springs definitely not! I have a 77 440 with zero deck pistons, closed chamber heads and a steel shim gasket and that combo comes out to 10.1:1.

The best you will be able to do without going through it completely is to use a cam that's designed for 8.5:1 compression. I believe Edelbrock makes a cam that would be perfect for this application. Your cranking compression with said cam should be around 160 PSI and that will be fine for 87 R+M/2 gas.

 

[q-ship]

What exactly are you trying to achieve?

The Thumper cams will give you an "overkill" sound with relatively low compression, but only offer a moderate (but noticeable) performance gain over stock, but work well with stock gears and converter, plus you would not have to spend money on milling your heads, all of which are cost savings.

If absolute performance is your goal, you will need to decide what trade-offs you are willing to live with, and how much you are willing to spend on gears, converter, carb, etc.

Defining what you want to accomplish is the first step. How much you have to spend is the second step. Parts selection is then relatively easy.

In any event, you will only be keeping the stock springs if you are doing a stock rebuild, but springs are relatively cheap.

 

[Schober Motorsports]

I'm really looking to go drag racing with it.

What I can for sure tell you guys is that,
I already have a 727 with a 2600 stall converter
Going to get an edelbrock intake
Going to get 4.11 rear gears

Also I don't mind running racing gas.

 

[YY1]

I ran the MP 284/484 in a 383 basic build. It was honestly a bit too tame for what I wanted, and I wished I had gone with the 509. The 484 had no problems with vaccum and was vey streetable.

Of course that was befre the much more detailed cam spec ratings we have now.

 

[67coronetman]

I like the mopar 292/509 it still works good and sounds great lots of tq and power.

 

[dantrap]

Go through the bottom end if you planning on full time Drag racing. Have your machine shop clean up the bores and install some current pistons to raise the compression when they freshen everything up. A good valve job and some pocket porting will help the 452 heads or do the home porting with the DC templates (before the valve job). I would say to go with mech. flat tappet setup with matched springs lifters etc. You can get a lot tech. info from Comp. Cams or Huhges racing. Those old DC grinds are ok but technology for cams has changed a lot in the last 40 years, you can do better. You need to pick how fast you want to go and how much coin you have to spend. Also with the cost of Race fuel at $9 or $10 bucks a gallon, have your mill built for 93 pump gas. It's a hell of a lot cheaper unless your building a full time race car. Good luck.

 

[Cranky]

Comp cams would the the last company I would call for a cam these days. The economy really knocked them into the dirt and they lost most if not all of their best people. I just did an engine for a buddy and he wanted to go with Comp (couldn't talk him out of it) and I ended up sending half of the dang parts parts back. This was for a Ford. Matter of fact, I think going with a custom grind is the way to go. Never seen a car go slower when swapping out for one but they all went faster. If you do go with a custom grind, you'll need to know everything about the combination including the weight of the car. And don't use stock springs even if they are new!! IIRC, MP says the 933 spring for that cam.

 

[Cranky]

I have a 77 440 with zero deck pistons, closed chamber heads and a steel shim gasket and that combo comes out to 10.1:1.

Meep, are you sure your compression is only 10.1-1 with that combo? My calculator says it has more.....it caught my eye because I have a similar engine but my pistons are a bit below deck and it figures up to 10.3-1. What is the CC's on your heads?

 

[jusglazin]

I agree with cranky on comp cams right now. I ordered a thumper for my 440 and it wouldn't even fit in the block. I had a machine shop check it and one of the journals was 1 thousandth two large. The old one fit right on so I know it wasn't te bearings. Their quality has really hit the bottom.

 

[dantrap]

That's to bad about Comp, I have used a few of their rollers and couple sets of lifters with good luck. Still using one now without any problems.

 

[BelvedereII]

Only way to know if the heads can take the lift is to set them up and find out. I agree the stock springs should be replaced; that might be a best first step so you can make sure there will be no spring bind or retainer contact in your head setup. Once you have that, you'll know your max---my ported 906's could take something like .560 but I didn't know until they were checked.

My Winnebago 440 is a '73, I put on my 906's, some TTI headers, aluminum intake and Comp's 230/236, .488/.491 Xtreme energy cam because I thought the low compression wouldn't go too well with anything bigger. Car is 3660lbs, 727 with 10" TCI (later switched to a 9.5" Dynamic) and 3.91's, ran fine but decided to go with a .509 which in my case was a Racer Brown .510 they call SSH-44. Also went over to 4.30's since the 3.91's were in a 741 case and I was wanting to go with a 742, so I don't have a side-by-side direct comparison of cams.

The factory pistons in that motor were about 1/8" down in the holes. The shop that I had do the machining for .030" over 10.25:1 pistons did not deck the block so my forged pistons are .025" down which brings it all to around 9.8:1 or so as guesstimating from the fact the 906's are ported and the chambers were cleaned up. I pulled the lifters and kept them in order for re-installing the .510 cam.

Anyhow, with the low compression pistons the motor ran just fine and the first couple times out with the the "six-pack" forged versions I did not notice much of a difference. The cam worked well enough with each set and I wish I had bought the bigger cam from the start.

B II

 

[Meep-Meep]

Meep, are you sure your compression is only 10.1-1 with that combo? My calculator says it has more.....it caught my eye because I have a similar engine but my pistons are a bit below deck and it figures up to 10.3-1. What is the CC's on your heads?

I CC'd everything and that's what I got. My heads are 915's with 2.14/1.81's and I think the Chambers came out to 79.5 CC +/- .3CC - or whatever the book says the 915's should be. My block has some huge bore chamfers - and when I say huge I mean HUGE - and the pistons have large valve reliefs that look more like a deep groove cut across the piston top. KB237 pistons (see pic). My cranking pressure with the MP .455" / 272 cam is 190 PSI. I believe if I had minimal chamfers and factory style six pack pistons that are more of a flat top profile I would have 10.5 - 10.7:1.

 

[Meep-Meep]

Forgot to attach pic. Here you go.

 

[Meep-Meep]

....Since we're on the subject, this is my 440 with the KB237's at TDC. If you look closely you can see the huge bore chamfer toward the top of the block in the empty cylinder behind the piston.

 

[Cranky]

Wow....the bore chamfer doesn't look too drastic but the piston does. Man, that's a canyon! Might think about rounding the sharp edges a bit too. Uncut closed chambered heads usually do come out right around 80cc....I think the old books I have say 70 and I've also found the same head to vary as much as 5cc from one chamber to another. The pistons in mine are flat tops with no reliefs....