230/251 Cam Specs...

[maineSS]

Your head # doesn't come up on my chart for either the 218 or the 230. It seems the 218 and the 230 did share one head, the 1120803, made from 1942-54. The other numbers I have for the 230 are 1311804 (1942-54); 1616823 (1955-59); and the 8:1 head 1676337 (1958-9).
Heavy duty truck and Ind/Ag engines didn't have vacuum advance distributors as it was assumed they'd be run at constant speeds most of the time. The PW engine doesn't have one, either. The "transfer slot" is the head area that starts just after the valves and slopes down towards the piston.

[pwdave]

heads

Maine, I guess from here the thing to do is cc the head and figure the compression ratio. all of my numbers are hand stamped, block and head both, the head does have the correct chamber, but at this point it looks like theres no knowing for sure until I cc . are all the 230-m37 cams the same? or are there some differences in years again? Dave.

[maineSS]

There are 2 different 230 cams I presently know of- the Early and Late OEM. I've heard the Early OEM may have come from the 218. The Late OEM may have been introduced in the first couple years of 230 production (sometime after 1942) or in the mid 50's- I've heard two different stories. Only way to know for sure is to measure it and compare it to Early/Late specs.

[maineSS]

Here are the complete .050" specs for the Oem Early, Late, Asche 380, and 400M as measured by Delta Cams. I had to scan at reduced DPI to get them to fit, hopefully they're readable. You won't find this data anywhere else but on the PWA forums. Pic #1 is the OEM Early, Pic #2 is the OEM Late, and Pic #3 is the Asche 380. The 400M will be on the following post.

[pwdave]

cams

thanks. Dave.

[maineSS]

And now for the 400M cam. All of the specs have been taken using the .050" lift method, so they're different than the ones you'll see in the old Motors manuals. It would be nice if we could find out how the original specs were done, but so far I've come up with nothing.

[T. Highway]

maineSS, Thanks for sharing this data. I've been thinking about modifying a cam for my M37 and this thread has been helpful.
What have you decided on for your cam?

[maineSS]

I sent the test results to Delta, and they said they would look at generating some new specs to try and improve on the Late OEM grind. What I'd be looking for is a little more in the 1800 Rpm area where an overdrive would boost highway speed without dramatically increasing fuel consumption. Supposedly the last 230's were making around 200 lb/ft torque @ 1600 Rpm, so I assume that was with the Late OEM cam. For now, I'd stick with that grind if I needed to get an engine going for practical truck-type use. The Early OEM made its peak torque at 1300 rpm, which is too low to help an overdrive- if you check the graph, you'll see it's already down noticeably @ 1800.

[T. Highway]

Thanks maineSS, I've been checking around and found that a guy in Santa Rosa CA has been doing custom cam grinds for flat heads with very good results. I'm going to contact him to see what specs would be recommended for the 230 / M37 engine for greater torque in the low to mid RPM range.

[Jason Mills]

I was just wondering the other day what camshaft that Vintage Power Wagons sells, and how it compares to a regrind? I wonder if they would release the specifications on it? (my rebuild had a regrind installed by me..)

[maineSS]

Highway- if you get specs, make sure they're complete enough to run through a good engine simulation program before spending money on a regrind. I'll probably be doing some more tests with Roadrunner, so I could send them along with Delta's if you can get them. Some grinders are very secretive about specs, so you'll likely have decide whether knowing in advance is better than paying and hoping for the best. It would be interesting to know what VPW's specs are, the fact they sell the cam with springs makes me wonder about the lift. Running it thru Roadrunner's program would also be interesting- if anyone has the cam, Delta will spec it for $10, and I'd be happy to send the specs along to Roadrunner. I wouldn't be surprised to find it's a high-rpm cam, but Performance Trends will know for sure!

[Jason Mills]

. I wouldn't be surprised to find it's a high-rpm cam, but Performance Trends will know for sure!

yeah, I think you just called it..

[John S]

After reading this old thread. I am wondering if you have run your truck on the road yet?