engine help
- Thread starter stafford
- Start date
CDNpontiac409guy
Banned
You could trade that stuff to me for some BBC Chev parts !
your question is "loaded"
.... hope you get some opinions here
your question is "loaded"
.... hope you get some opinions here
I remember someone on this board said the MT crossram can give you problems with uneven fuel distribution but I've never used one so I don't know. It does look cool though. The heads will support 500hp without any work but a mild cleanup of the bowls and exhaust ports won't hurt. You could put in a 454 crank and a good solid lifter cam. With headers this combo will make 500hp no trouble. I guess it all depends on how much money you're willing to spend. What part of MN are you from?
The combo I'm building is supposed to be good for about 500hp @ 5600rpm and 520 ft lbs according to Curt Harvey, CH Enterprizes. It's not finished yet so I can't say for sure.
It's a 474ci stroker. That's a crank from a 454 big block that's modified to fit a 409. My actual compression will be about 9 3/4 to 1, the heads are 690's, high performance similar to yours. I did a bit of bowl blending on the intake side and some minor porting on the exhaust side. The cam is a hydraulic roller with 238 & 248 duration at .050 with a 110deg LSA the lift is about .600 with 1.7 rockers. I've got a factory dual quad with factory carbs and 1" open spacers. So far I'm using 1 3/4" long tube headers. 2" would be better. I'm waiting patiently for the roller lifters to arrive so that I can assemble this thing. When I get it done I'm planning to dyno it and I will post the results.
I went with the stroker crank because my crank was cracked but you should be able to make the same HP with the stock crank, at a higher RPM. If I was aiming at 500 plus HP I would use pistons designed for the stroker combination, they're lighter. And longer aftermarket rods. No problem going 7000plus rpm with that setup. Lots of guys are running 11:1 compression without problem. The roller cam's nice but expensive so I'd consider a solid flat tappet with lots of lift and about 254 & 264deg. duration @ .050 and a 110deg. LSA. I'm sure that MT crossram will make more torque and HP than the factory intake. With a decent valve job and 2" headers this engine would make lots of power and it would rev like crazy. It would be a blast to drive. I hope we get some more suggestions.
It's a 474ci stroker. That's a crank from a 454 big block that's modified to fit a 409. My actual compression will be about 9 3/4 to 1, the heads are 690's, high performance similar to yours. I did a bit of bowl blending on the intake side and some minor porting on the exhaust side. The cam is a hydraulic roller with 238 & 248 duration at .050 with a 110deg LSA the lift is about .600 with 1.7 rockers. I've got a factory dual quad with factory carbs and 1" open spacers. So far I'm using 1 3/4" long tube headers. 2" would be better. I'm waiting patiently for the roller lifters to arrive so that I can assemble this thing. When I get it done I'm planning to dyno it and I will post the results.
I went with the stroker crank because my crank was cracked but you should be able to make the same HP with the stock crank, at a higher RPM. If I was aiming at 500 plus HP I would use pistons designed for the stroker combination, they're lighter. And longer aftermarket rods. No problem going 7000plus rpm with that setup. Lots of guys are running 11:1 compression without problem. The roller cam's nice but expensive so I'd consider a solid flat tappet with lots of lift and about 254 & 264deg. duration @ .050 and a 110deg. LSA. I'm sure that MT crossram will make more torque and HP than the factory intake. With a decent valve job and 2" headers this engine would make lots of power and it would rev like crazy. It would be a blast to drive. I hope we get some more suggestions.
CDNpontiac409guy
Banned
Yes Stafford, lots of guys are running the stroker combination with a 454 crank. Easily will make the 500 HP number your looking for, but you will lose the inhereted "INSTANTANEOUS RPM" of the 409
.... But, you can have your cake and eat it
427 crank. Builds 446-452 CID. Peg your compression at about 10.7:1 with light weight forged pistons, aftermarket BBC con rods, full floating pins. Remove excess weight from the crankshaft as practical, and balance the assembly.
Prepare the heads as stated by the other guys. With a cam at 250-260 dur @ .050 and about .600-.620 lift on a 110 CL, using roller rockers and valve spring seat pressure at approx 140.
With your M/T manifold, a pair of 600 DP Holleys, and 2" tube headers into 3 1/2" collectors.... I could see 550 HP without a problem
.... But, you can have your cake and eat it 427 crank. Builds 446-452 CID. Peg your compression at about 10.7:1 with light weight forged pistons, aftermarket BBC con rods, full floating pins. Remove excess weight from the crankshaft as practical, and balance the assembly.
Prepare the heads as stated by the other guys. With a cam at 250-260 dur @ .050 and about .600-.620 lift on a 110 CL, using roller rockers and valve spring seat pressure at approx 140.
With your M/T manifold, a pair of 600 DP Holleys, and 2" tube headers into 3 1/2" collectors.... I could see 550 HP without a problem