Hello,I recently bought a formula with 383tpi engine,the problem is its pinging as soon as its pass 2000 r/min,half trottle or more,I think the problem is the heads maybe.This is a what the seller told about the engine:Scat 383 internals with hypereutectic flat top pistons, 4 bolt main block, 64cc cast iron heads, large valve and ports, 2.02 intake and 1.65 exhaust valves, 219/219/560 roller lingenfelter cam, 24cc ford motorsport injectors, 58mm throttle body, headman headers, high volume oil pump, custom chip, ported intake and plenumn. 1.6 crane roller rockers and lifters. (I dont know if its hydrauic or mechanic lifters,but they are ticking alot)moroso 7qt oil pan. 2500 stall torque converter.BUT!!after I looked at the heads casting #I found this:#3932454.I found out it was heads from a 307or350 truck engine with the smallest valves.Can these heads be machined to fit big valves?Please help me out here what to do to get rid of the pinging.

 

Well, if this part was a lie, what else do you think is true?
It looks like a bunch of parts someone threw together hoping it would run fine .
If it was bored .030 and the block decked the C/R is aprox 12.5:1
If the block wasn't decked, the C/R should be about 11.75:1 . 76cc chambers would give 10.23:1, borderline for 93 octane gas depending on what cam is in it.
This would be one of the reasons that 1/2 of the questions posted here are engine combo questions.
Your best bet is to pull the heads off (since they ain't gonna work) and measure the actual bore, measure the actual stroke, measure the actual deck height. Without these you would still be guessing at the C/R.
You want to run it on 87 octane or 93 octane gas?

 

^^ agreed!

flat tops will push compression to 11 to 1 with a 64cc chamber with a standard .040 gasket and zero deck. TOO much with iron heads and pump gas with that cam.

its pinging cuz its got too much timing and too much compression. you really need to change alot of stuff about that motor

new heads are a must. Aluminum 64cc's would be nice, but be prepared to drop 1000-1300 or so

 

I will run the engine on 98 oct gas..we have only 95-98 oct here in Norway.

((flat tops will push compression to 11 to 1 with a 64cc chamber with a tandard .040 deck. gasket and zero ))

I am pretty sure its zero deck.Whats the best comp to run on this engine?I also wonder how I find out if its hydraulic or mechanical rollerlifters?Whats the best head for this engine`?

 

that cam is lingenfelters 219 cam. Is a hydraulic roller cam. best compression for that setup is around 10.5 to 1 but i dont know for sure since i dont have the valve timing events for that cam. My 383 is a 11 to 1 piece with a bigger 230/245 grind and that puts me at 8.3 to 1 dynamic compression. you generally want to be around 8 to 1 with a pump gas motor. you can go up to 8.5 to 1 with aluminum heads but on iron i think its best to stick with 7.5-8 to 1 dynamic. You need the cam events to figure out that compression. At 11 to 1 your setup will be in the 8-8.5 to 1 area and will need good octane gas.

I'd start with running 98 octane for now and playing with the motor timing to see if you can get it to run somewhat normal. But those heads arent helping and i'd replace those with something else for sure

 

Thanks for helping out here guys Would the engine run better without the 1,6 rockerarms?the engine is running rough on idle,and seems to be running a bit rich.I checked for vacuum leaks but cant find any leaks.I have tried different timing but it seems to be the same with the pinging all the time..checked the plugs and they have nice brown colour

 

I changed the fuel pump today,and adjusted the timing to 6"..The car run fine now ..the pressure dropped to 25 psi with more than half throttle and up..Now i can give full throttle and the car spins out 1 and 2 gear and continue spin in third gear..runs wery good now
----------
whats the cc on these heads,cant find info anywhere..:#3932454