Blocks are Dart Big m 9.8 height decks 509's
Brodix heads, carrillo rods, carrillo crank, Hyd roller cam, sng 1050 carb N/A making 635HP @ 6000 RPM's. These motors only have 10 hrs on them.

9.3:1 compression
4.50 bore
4.00 stroke
6.135 rod length

Question is.
1. Can I slap a BDS 871 on top like it is and go or will I need to change pistons and cam.
2. What Hp will I get with 871's and 509 ci.

What type of fuel did you want to run?



Darrell.

To run 93 octane, you would need to reduce your comp ratio. I would think you should be able to make 750-800hp easily with the right combo.

So basically cam and pistons change to run on 93 oct Thanks guys

You can bolt them on they way you have them all ready, you just won't be able to utelize them as much as you could

If you are good at tuning, you could run 2-4 lbs non intercooled oe 4-6 lbs with an intercooler. Of course if you want to lower the compression to 8.2 or so, you could run 5-7 lbs non intercooled, 8-10lbs intercooled and another 100 hp over the high compression set up.

I spoke with diamond pistons and the said I could go with what I have or they could releive my pistons a little. Debating on going ahead and boring my darts to 4.6 to 532's

I thought you sold those engines??

I traded them then the guy backed out of the trade a couple days ago. So I got them back. I would like a 10.2 dart set-up but these 9.8's is what I have to work with now.

Why not use a carburated Whipple if you want to stay carb. They love some compression and 9.3 is not out of the ordinary. I have done them up to 10.2:1 and 9.5-10:1 is not uncommon.
I did a set about 1 1/2 years ago. They were a pair of my 750 NA's. They are 598, 10:1 with a 1050 dom. We just removed the intake and bolted on the Whipple and went to the dyno. They made 942 hp and 1070 ft lbs at 5.5 psi on 93 octane and 1020 hp and 1190 ft lbs at 8 psi on 100 octane