My 309 build....

[Speakfordadead]

I know it's not a truck motor, but it is an old school type build.

Who knows what a 309 is??? I'll hint at the crank number.... 1178

 

[DoubleDingo]

Never knew there was a 309. Is it a 305 or 307 bored out a little?

 

[Speakfordadead]

Most odd numbered Chev builds are from the racing industry. This motor was designed when the 327 came out, they had a 310 cube limit on most dirt tracks. Some guys were lucky enough to run across the 302 motors. so, if you put:

#3970010 4bm block at 4.045 bore
#L1101 .085 Pop up pistons (060 over 327)
# 5.7 Powder Rods
#1178 crank (3.00 stroke)
#291 Heads
# 11.1:1 Compression

you get 309 Cu In and over 325 HP at less than 7000 rpm....

Why not use a 283 crank??? Journal size. 1178 crank is a large main crank.

At 6500 rpm the thing sounds like a formula car..... I'm excited. Can't wait to spin it..... teehee

 

[Green79Scottsdale]

Sounds like a bored 302. That is a DZ302 '69 Z/28 forged crank, IIRC.

Are you going .045 over, or .060? I can't do the math in my head right now. Your block specs show .045 over, but the piston specs say .060. Just curious is all.

Large journal bearings spin faster than small journal bearings, just sayin.

Do want videos of when it is running! Should be a fun motor. What are the cam specs?

 

[Green79Scottsdale]

Forgot ask, what is this going in? Dirt track car?

 

[DoubleDingo]

Most odd numbered Chev builds are from the racing industry. This motor was designed when the 327 came out, they had a 310 cube limit on most dirt tracks. Some guys were lucky enough to run across the 302 motors. so, if you put:

#3970010 4bm block at 4.045 bore
#L1101 .085 Pop up pistons (060 over 327)
# 5.7 Powder Rods
#1178 crank (3.00 stroke)
#291 Heads
# 11.1:1 Compression

you get 309 Cu In and over 325 HP at less than 7000 rpm....

Why not use a 283 crank??? Journal size. 1178 crank is a large main crank.

At 6500 rpm the thing sounds like a formula car..... I'm excited. Can't wait to spin it..... teehee

That is info I was not aware of. Very cool. Sounds like an engine that could bring big smiles.

 

[Stewzer55]

Sprint car winged or wingless, "stock" or Modified? If you ask me, there are few sounds better than a 410 engine, or 30 of them on a short dirt track going sideways.

 

[Driver4r]

I've contemplated putting a 302 in my truck. I plan to put 4.88's in it. So that would help with the absence of torque. And I plan to spin it to 10k if I do build it.

 

[MadOgre]

How much torque does that little puppy make ?

 

[Driver4r]

The gm dz was never meant to make torque. They just needed it to rap to the moon. And cause there was a cube limit.