I'm thinking about installing this cam in a basically stock .030 over 312 that I will be putting in a '46 Mercury coupe with a 5 speed and 3.70 rear.  I would like to move the torque band down to a livable level.  If I advanced the cam 2 to 4 degrees would that help?  Seems to be a lot of valve lift, but if I use 1.43 rockers, I can bring the lift down below .500.  Any cam gurus out there who can give some advice to a cam dummy?  Should I just get another cam?  Trying to use what I have. OOPs.  I'll try the picture one more time.

Butch Lawson

Manchester,  TN

This all depends on what you call livable.  .337 lobe lift and 250ish degrees duration (@ .050" I'm assuming) is a big cam, which will probably be on the ragged edge of streetable, if not a full out race cam.  Changing the cam timing is a way to compensate for a cam that is slightly bigger or smaller than you wanted, but it doesn't change it by a whole lot.

Advancing will shift the power band down but it still may be more cam than you want.


Lawrenceville, GA

Did they get the test sheets mixed up? Why does the spec sheet call for hydraulic roller lifters?

I guess I already figured that Charlie, just needed somebody to tell me.  Will probably send it to be reground to a more streetable cam.  Thanks for your reply.

Butch

Butch Lawson

Manchester,  TN

I asked about that Sandbird and it has something to do with their computer program.  They said the timing events would be accurate for solid lifters.

Butch Lawson

Manchester,  TN

I think you are making a wise choice by going smaller with the cam. Seeing that they already have the cam a couple degrees retarded with that much lift and duration I wouldn't consider any advance moves without carefully checking the valve to piston clearances at overlap.

Butch.
While that camshaft is marginally on the large side for a stock type build and especially if it is going to be a daily driver, I did the numbers and with it installed at six degrees advance (102° intake lobe centerline), it would be doable for a Saturday night cruiser.  This cam would be lumpy and unsuitable for an automatic transmission without some kind of stall converter but would definitely be an attention getter at the exhaust in the right application.  The intake to valve clearance at the edge of the cylinder wall would be getting close and you would be prudent to check that during assembly but if the intake lift is only increasing 0.025” with the additional four degrees of advance versus those numbers shown on the cam card, it is expected to be fine.
 
Based on your cam sheet, the camshaft is 285°I/290°E adv duration, 245°I/253°E dur at 0.050”, and ground on 108°.  Here are the SCR and DCR numbers with the camshaft installed at 102° intake lobe centerline. I assumed only a light mill on a set of ‘G’ heads with the pistons level with the deck so the compression ratio is a variable in the calculations.

Lorena, Texas (South of Waco)

Thanks Ted.  That's good info, but since I plan to drive this car a lot, I think I'll send the cam to be reground to a more moderate duration.  Something like 224 @ .050.
Butch



Butch Lawson

Manchester,  TN

If you link to John Mummert's site, he stocks a cam @ 224 degrees & another @ about 228 & they are not regrinds. Also has new lifters in stock, which you will need if you regrind your existing cam.  Using used lifters is not recommended with another cam..


Paul

Thanks Paul.
Butch


Butch Lawson

Manchester,  TN