can any one tell me what the bore measures on a big bore 780 kit i have one from hauck on a spare motor just wanted to know what it measures ...
x2ryder
New member
72.90 are the pistons. Stock 62 stroke.
there is actually 2 differnt ones, 72.9mm, and also a 73.9mm were built, wiseco makes pistons for both of them, hauck also built both of them.
x2ryder
New member
Wiseco said they have not sold any of the 73.90 srx pistons in for 5 years. I tried to get them. Hauck says they are out also.
thanks guys i have finally pulled head and measured and it is a big bore ....but it is olny a 700 bore instead of the 780....so now i have a motor that looks to be a 600 but was made into a 700 ....so i should be able to run regular 700 power valves ? guess i have a nice sleeper motor lol ....guess i should have just left it in the sled ...whats a good price to sell this motor for complete ?
oh also i forgot ....it has 8df00 heads them are 600 heads rite ? and if put on a 700 bore they would have to have been shaved to bring the compression back down to 120 ? i thought i read stock 600 heads on a 700 would raise compression to 150 ish ...
8df heads are 600 heads, they would raise the compression on the 700 engine.
(73.9mm)they are still available from wiseco, they changed the part number a couple years back, they are now a very thick skirt and heavy piston. The reason you cant buy pistons sometimes from wiseco is because if someone like hauck or whoever has a set custom made they hold the rights to those and youd have to purchase those thru the original order person.
Also if wiseco is out ,alot of times they need a certain amount to make a run, this happens to me alot with the 72.9mm pistons.
(73.9mm)they are still available from wiseco, they changed the part number a couple years back, they are now a very thick skirt and heavy piston. The reason you cant buy pistons sometimes from wiseco is because if someone like hauck or whoever has a set custom made they hold the rights to those and youd have to purchase those thru the original order person.
Also if wiseco is out ,alot of times they need a certain amount to make a run, this happens to me alot with the 72.9mm pistons.
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so the heads have been cut to make compression normal ? they are on the motor now with 120 straight across ..if they werent shaved compression would be around 150 ish correct ?