Technical flathead clutch size

I'm building a 59a engine for my 37 pickup running a 39 trans and 3.25 banjo. It will be bored and stroked to 286ci, edelbrock 4 barrel, edelbrock heads, 1007B cam.

What clutch size do you recommend? 9 or 10? Should I run a lightened flywheel?

I have a flywheel for both 9 and 10 inch clutch sizes. The 9 inch flywheel is the pot type with large lip around it.

Suggestions? Thanks

 

Forgot to ask, will the 10 inch pressure plate fit in early top loader case?

 

i have a `37 1/2 ton with a 239", milled heads,single carb, Max-1 cam and a 3:78 with a Columbia. the clutch is a 9" that was cut [it weighs about 22 lbs], the motor revs quick [not a lot of flywheel weight to get spinning] and it pulls away from a dead stop with out having to rev the motor excessively. if i had it to do over again, i wouldn`t change a thing.
tom

 

When you say "cut" do you mean you had the entire lip machine off?

I'm leaning towards the 9in as I already have a new pressure plate and clutch for it. Although the flywheel ring gear is pretty chewed up...

 

yes, the entire lip on the flywheel was removed, you want to remove as much weight from the greatest diameter that you can. flywheel ring gears are cheap, replace it.
tom

 

With all that matieral removed from the flywheel will it still be streetable? How light is too light for a pickup?

 

Just wondering if it would bog down between shifts or something?

 

see my first post!

 

X2..

 

I use a lightened flywheel (22#) and a 10" diaphram clutch. Works real good

 

I have a similar setup in my 38. I machined the lip off of the dog bowl 9" and had it rebalanced...what a waste of money. After "rebalancing" it nothing changed. The machine shop (I've worked with them for 35 years) noted that it was dead on the money and no material added or subtracted. My 38 with the modified dog bowl works perfectly and the flattie is a 255 inch with sharp heads two 48's and a melling camshaft.

 

On the early case and 10" clutch...look at serial to date the case, or look at first inch or so of the bellhousing where it bolts to engine. '32-34 taper right from the front, and will not clear 10" or 11" without some grinding of bosses. 1935 ans up go straight back for about an inch and also have very slightly raised clutch shaft because Long clutches up to 11" were available then.