Thread: Engine Combo

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Should make good power from about 3,000 to 6,500 rpm's. You'll need a loose converter, somewhere around 3,000 stall for a street motor, a little looser than that together with some gear for a drag motor in my opinion.

Your static c.r. will be 10.109:1 with this combo assuming 0.030" over, a 9 cc gasket volume and zero deck, so the cam you listed will be right at the top end of the scale. You may not build maximum achievable cylinder pressure with this combo, but you've got enough cubic inches to make up for it. Using a piston/head clearance of around 0.045" to 0.050" (0.035" to 0.040" on a small block, but the rat has a bigger bore than a small block, so the piston has more room to rock in the bore), you should be able to operate on cat piss pump gas.

It's like Dave said, it's hard to argue with dyno results. Usually when the magazine guys do a dyno thrash, they'll try 2 or 3 different cams, manifolds and carbs.

Now, some of you guys on here are gonna figure the c.r. for yourselves and you may not get my same figure. With a domed piston, you have to deduct the dome volume from the cylinder volume to arrive at a true cylinder volume upon descent of the piston. (.7854 x 4.280" x 4.280" x 4.250" x 16.387 = 1,002 cc's in the cylinder....but wait....the dome occupies 18 cc's of volume and it is attached to the piston top, so when the piston descends, the amount of mixture drawn in will be 1,002 less 18 = 984 cc's in the cylinder.

So we would add 984 and 119 and 9 and get 1,112 cc's in all available spaces. This will compress into the gasket of 9 cc's and the combustion chamber volume of 101 cc's (because now, the piston dome is in the chamber taking up volume so we have to deduct the 18 cc from the 119 cc chamber).
1,112 divided by 110 = 10.10:1