Jeep Strokers

So I finally had some time left to do a little meassuring on my engine; First I clayed it to see some numbers on valve to piston clearance with the new camshaft,and I think it will be OK even with some decking of the block and shaving to the head,the thickness of the clay straight under where the valves are ended up being 0.181" (without headgasket)and there was not any marks from the valves at all,but can that be a correct reading?

Then we checked the piston to deck height and found out that it was 0.0346 (Renix block 258 rods and stock 4.0 pistons) since the new Speed Pro hyper pistons has 1.592 pinheight versus the stock 4.0 pinheight of 1.601 the piston to deck height will be .0346+.009=0.0436,can that be right?

It seems there is something not really right here,we double-checked every number and got the same readings every time,everywhere I read about quench and decking the block it always says to deck the block 0.020 to get the pistons flush with the deck,but that is not even near in this case as I see it,and IF these numbers are correct,is it possible to deck my block so I will get the pistons to sit @ 0 to the deck,I would like it to have a 10.3-10,5 C/R since that is whats recommended for the camshaft.

str8-6 wrote: It seems there is something not really right here,we double-checked every number and got the same readings every time,everywhere I read about quench and decking the block it always says to deck the block 0.020 to get the pistons flush with the deck,but that is not even near in this case as I see it,and IF these numbers are correct,is it possible to deck my block so I will get the pistons to sit @ 0 to the deck,I would like it to have a 10.3-10,5 C/R since that is whats recommended for the camshaft.

Your numbers are probably correct.
With a combination of 4.0 block, 258 crank, 258 rods, and Speed Pro hyper pistons I'd expect the deck clearance to be 0.0385" (+/-0.005") so your measurements are in the ballpark.
The 0.020" figure for decking the block applies to the 4.0 rods/IC944 pistons combo and even then, the pistons would still be 0.007" (+/-0.005") down the hole.

OK thank You Dino,that makes it a bit clearer about the decking issiue,but the number I've got how far down the pistons are is with my old stock 4.0 pistons still in the engine so with the Speed Pro's they will end up being 0.0436 down the hole ,is it possible to deck the block that much?

Yeah, just shave 0.040" from the block and use shorter pushrods to correct the lifter preload.

I don't think you can run into piston/valve clearance issues?, we run flat top pistons and big valves in the 4.6 in the race car with the deck and head milled quite a bit, we also run the biggest hydraulic cam Crower makes and have no clearance issues!

That will leave the pistons .0036 down I presume,so how much do I need to shave the head to end up with a 10.3-10.5 C/R?

Got some new ideas about carburation: the old head I been using up to now show some signs of bad fuel-distribution #1 cyl. seems to have been rather lean if You look at the exhaust valve and combustion-chamber # 2 and 5 looks OK #6 looks a tiny bit lean and #3 and 4 have been running really fat,but thats the usual problem with inlines and and carburators and even with a aftermarket intake the problem is still there so my new plan in this area is to run 3 Weber 48 IDF (downdraft) instead of the Offenhauser manifold and that old Holley 600,I'm messuring and thinking right now ,there will be some very good throttle-response and horsepower will probably go up,so whats to loose more than a couple of thousnad swedish crowns and a lot more work... Not sure to go that route yet,there are not so much sparetime in my life right now so the enginebuild has to have prio one,but if I can get that done in time I'll get started to make some drawings of a IR-manifold for those Webers... Cool looking setup with 6 stacks in a row also.

IH 392 wrote:I don't think you can run into piston/valve clearance issues?, we run flat top pistons and big valves in the 4.6 in the race car with the deck and head milled quite a bit, we also run the biggest hydraulic cam Crower makes and have no clearance issues!

Clayed it last night, and without headgasket and the stock 4.0-pistons (SpeePro hypers will sit .009 further down) stock valves and we did not see even a mark in the clay,we meassured the thickness straight under the valves and got a reading of 0.181,so I'm not so worried about that anymore,the camshaft is a Lunati Vodoo (the biggest they got... ) adv.dur. @ 006 is 271 in 279 out and 0.050 dur. is 226/234 deg.intake C/L 106 , lobe sep. 110 , lift @ valve is .527/.548 (in/out) ported 7120 ,4.7 liters around 10.4 C/R and a 4 barrel carb and tuned homebuilt hedders in a T-hot Roadster car's a lightweight @ ca 880 kilos = 1800-1850 pounds???? aint got the formula for converting kilos to pounds) I think it will get the power enough to move under it's own power at least... Oh almost forgot : a 75-100 hp shot of nitrous if it gets to slow...