Hi guys; Which is the max. bore for a 366 truck block? can be bore to 4.250? thanks

I found this information on the HOW "TO BUILT MAX PERFORMANCE CHEVY RAT MOTORS" book .

"366T Mark IV and Gen.V blocks are used in large ,medium and heavy duty trucks and have tall decks and exceptionaly thick cylinders walls along with four-bolts main caps.they have a standard bore of 3.935" and can be bored .125" over. The Gen.V 366T has a one piece rear main seal.They have limited performance applications because even with .125" overbore the possible cubic inches are relatively small.They have been made from 1966 thru the present ".

3.935" -standard bore
+ .125 -overbore
____________________
4.060 -
This is the same bore as a 350 motor + .060 over
I hope this helps ,HAPPY NEW YEAR 2005 ! graemlins/beers.gif

Hate to tell this, start looking for a new block. Building that can be done with lots of money and minimal returns. Been there done that kind of deal.

At .125 over, my math says that's just 390 cubes. All that weight for just 7 inches over a small block stroker. If you could drop a 4.0" stroke crank in it, that would make it 414 - long arm, small bore, something along the lines of a small Olds or Poncho...or a 305. If it's a deal, get the main caps off of it since they're the same as a production 4-bolt block, plus the crank will be steel.

Daveseitz,I am not going to look for a new book because if you read it correctly it NEVER said it can not be done it SAID with ".125 the posible cubic inch is relatively small" ,I think this book only needs a GOOD lecturer ;) , as you mentioned a lot of money ,$350.00 6.535 long rods ,intake spacer or tall deck intake,slip collar distributor and all with minimal returns graemlins/thumbsup.gif ,this parts just adds more weight to the motor.
I am using a tall deck block my self with the long rods and spacers , it is a 427Tall deck block ,with this block you can make a lot of large cubic inch combos ,but with a 366 you will always be limited to make small cubic inch Big Blocks only .
MyBoTy your numbers are correct 388.38 cubic inches ,390 aprox .

This 388 cubic inch motor can be done with a 350 block ,3.75 400 crank and same bore .060 over :
.7854 x (4.060 x4.060 )x 8 = 388.38 cubic inch

I to was given a trk 427 with steel crank am considering the building of this motor , have spacers and 1979 peanunt open chamber heads , havn't bought the rods or pistons yet . DO the car intakes on top of the spacers need a slip collar dist ? Hadn't heard about that issue , thought a pass dist worked OK ? what do the numbers work out to on the 427 at .125 over ? and a cam of choice for a full drag chevelle 1966 , 2500 pds car 5:38 posi -350tth thanks

I understand what you are saying, yes it can be done. Thats the beauty you can do just about anything with engines. My point was replacment of a SBC with a BBC 366 combo can be done. The hp gains + added weight + additional costs would not be attractive. If you had a BB in and just needed a replacement for the time OK. But to use a 366 foundation for performance build no. My 427 tall deck went to a guy building a stroker 4x4 mud truck.

There are companies making aluminum intakes for TD that you do not got to use the slip collar intake to put the distributor .400 down the hole and no need to use spacers but they are expensive and the rpms are for hight rev motors 3000-8500rmps ,the TD came with an iron intake with this done (.400 down )that is why the distributor is the same lenght ,another thing I made some mods. to some brackets to make them fit (alternator ),remember the alternator it is bolted in the pump and the head and the TD block is .400 taller from pump up .

PI % 4 X (BORE X BORE ) stroke x # of cyl.

.7854 X (4.375 X 4.375 ) 3.75 X 8

= 450.99
= 451 cubic inches

I am no expert but do a search and find a good cam for you combo graemlins/thumbsup.gif

APPRECIATE THE POINTERS on tall decks-Javier , also heard hedders cane be a pain to fit - marko

Wrenchadblues, I use the SUMMIT headres part -#SUM-G-9010 they are 1 3/4""promary tubes and 3"EX. they fit like a glove .but I am using the tall frames mounts to clear my 8 quarts oil pan ,may be this give me the clearence I needed if you got the low mount you got to take your chance ,I don't got hood problems, I am running a stock cowl induction hood .