UPDATE: 5/24/13 Don't build a motor like this. It runs good, sounds good, but make now power. Check out this link. 1963 Ford Falcon on dyno
So my budget motor build is steadily getting more expensive. Now that I have my block back I have all the parts to put the shortblock back together. Since I am going to use the old TRW L2249N pistons I will need a way to lower the compression so I can still use my Vortech Supercharger. I happened to have the 289 that I pulled from the car when I brought it home.
The 289 uses the same block and pistons as a 302, only the crank and rods are different. The crank has a 2.87" stroke vs a 3" stroke. The rods for a 289 are 5.115" long vs 5.090" for the 302. So if I use a 289 crank with 302 rods, the pistons will stay below deck and lower the compression ratio. There is a ton of information to sift through on this. Lot's of people say if you do this you will not have the proper quench and you motor will be a turd. Others say it really doesn't matter. So it comes down to who you believe.
I was almost convinced that it was a bad idea, but I stumbled upon a post in a forum where one person had done this very thing without knowing he had done it. His motor ran fine and he didn't realize his mistake until he had taken it down for a rebuild. So I am thinking if his motor ran good, my should too.
So here is my assembled 289 short rod motor. My compression will still be in the 9's thanks to the huge domes on the L2249N's, which should work really well with my supercharger.
In this picture you can see how far down in the bore that the piston ends up when you use 302 rods with a 289 crank.
So my budget motor build is steadily getting more expensive. Now that I have my block back I have all the parts to put the shortblock back together. Since I am going to use the old TRW L2249N pistons I will need a way to lower the compression so I can still use my Vortech Supercharger. I happened to have the 289 that I pulled from the car when I brought it home.
The 289 uses the same block and pistons as a 302, only the crank and rods are different. The crank has a 2.87" stroke vs a 3" stroke. The rods for a 289 are 5.115" long vs 5.090" for the 302. So if I use a 289 crank with 302 rods, the pistons will stay below deck and lower the compression ratio. There is a ton of information to sift through on this. Lot's of people say if you do this you will not have the proper quench and you motor will be a turd. Others say it really doesn't matter. So it comes down to who you believe.
I was almost convinced that it was a bad idea, but I stumbled upon a post in a forum where one person had done this very thing without knowing he had done it. His motor ran fine and he didn't realize his mistake until he had taken it down for a rebuild. So I am thinking if his motor ran good, my should too.
So here is my assembled 289 short rod motor. My compression will still be in the 9's thanks to the huge domes on the L2249N's, which should work really well with my supercharger.
 |
| 289 with 302 rods TRW L2249 N pistons |
 |
| Piston depth when using 302 rod and 289 crank |
Comments
Post a Comment