Compression for boost application.

Toyboytoh

Active member
I really didn't look into this. Just a whirl of asking you guys.
Can you put a 300 head on a 240?
I've changed my whole ignition system to only still get backfire. Reset timing aswell and I've got blow by on the motor. So I'm taking the beatin up 240 out of my little truck and doing a rebuild. So I know low compression is good for forced induction, and putting on a 300 head would make that pretty East no?
 
Toyboytoh":3igttsq1 said:
I really didn't look into this. Just a whirl of asking you guys.
Can you put a 300 head on a 240?
I've changed my whole ignition system to only still get backfire. Reset timing aswell and I've got blow by on the motor. So I'm taking the beatin up 240 out of my little truck and doing a rebuild. So I know low compression is good for forced induction, and putting on a 300 head would make that pretty East no?

Yes it will drop the compression to the low 8s.

The connecting rod small end went from .912" to .975" after 1968: What year 240 do you have?
 
Hey man. Thanks for the fast reply and straight forward answer. I don't know what year the little bugger is. But she's the blown 240 build on this thread. I never bothered to look at the number under the head.
Because 240's are hard to find now I figured instead of rebuilding the head, I'd grab a 300 head and slap it on her, get some new pistons and call it a day. The guy here to machine, and rebuild my motor wants 7grand. So I'm trying to cut some corners and get the Superchargered six healthy again and crank the boost! ;)
 
The reason for asking is if the engine has the rods with the .912 pin you can use off the shelf forged pistons for the Ford 351W V8.
 
The block casting number starts with C5TE.
It is located on the crankcase down by the starter.

The head will also start with C5TE and that number is upside down on the driver side under the front lip below the water outlet.

The best way is to pull the pan to see if the rods have the oiling hole on the big end of the rod.
If not then they are the .912" pin rod.
They are getting hard to find.

7 grand is seems high.
I've got 6 grand in this long block
CNC ported head with Chevy 2.02/1.6 valves, 7/16 screw in studs, Comp pushrod guild plates and Comp valve springs and retainers.
Comp Ultra Pro Magnum™ XD Rocker Arms 1.6 ratio
Spring pockets cut 1.5" for spring locators and shims.
Head bolt holes spot faced.
Jones cam 23*/232*, 288*/288*, 534", 112*LSA
C6AE 240 rods, polished, shot peened and resized with ARP bolts.
Custom Autotec pistons.
Block was cleaned, magnafluxed, line bored, decked, bored and honed. Also spent 4 hours deburring the entire block including the cam tunnel.
Crank, pistons and rods were installed to check for zero deck clearance. Then they were removed for final deck cut.
Block, heads and covers primered then shot with Ford blue
Crank was balance with McLeod steel flywheel and Centerforce pressure plate.
Assembled with ARP head and main cap studs
Clifford intake from Ebay and EFI exhaust from Pull and Save
 
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