im building a 496 stroker and plan on running a 150 shot of nitrous. so my questions are #1 which are better rectangle or oval port heads, and #2 if anyone has any suggestions on any certain type of heads would run the best....im trying for 10.5 to 1 compression. thanks
Which is better
- Thread starter WarWagon
- Start date
- Status
Rectangle ports will breathe a LOT better for your stroker on juice.
Aluminum heads will disperse heat better than cast iron so they're a better choice if you're running 10.5:1 compression.
If you're running a high lift cam, make it a roller.
Since you're running Nitrous your pistons, rings and other rotating assembly needs to be stronger, I'm not an expert so hopefully some others will chime in with that info!
Good luck on the build bro!
Aluminum heads will disperse heat better than cast iron so they're a better choice if you're running 10.5:1 compression.
If you're running a high lift cam, make it a roller.
Since you're running Nitrous your pistons, rings and other rotating assembly needs to be stronger, I'm not an expert so hopefully some others will chime in with that info!
Good luck on the build bro!
Sounds like good advice/info to me. If you don't already have heads and you have to buy some unless you find some used for dirt even then it may be questionable if they need valves or other work. Generally spend your money on aftermarket heads.
You're at that break even point, honestly. If you were not squeezing it and rpm was below 5500, oval ports like 049's with a good clean up port and valve job would make excellent street heads. Generally, depending on cam selection, valve size, etc... rectangles won't make more power below 6000-6500 rpm. The fact that you plan to run the 150 squeeze on it though kind of tilts it to the rectangles unless you are going to limit rpm to 5500 or so, then I wouldn't spend the money, they won't help.
I ran a pair of 540's in my Donzi for 20+ years and tried every combo you can think of and below 6000 rpm, even with all those cubes, the Dart oval ports made more power in the 6000 rpm range, even with the 250 N20 shots on them. Boat engines however are different from street engines, which tend to rev faster and higher, so if your cam and valve train are going to be set up for running north of 6000 rpm and you're running enough gear to compensate for the torque loss at street speeds, go rectangle.
I ran a pair of 540's in my Donzi for 20+ years and tried every combo you can think of and below 6000 rpm, even with all those cubes, the Dart oval ports made more power in the 6000 rpm range, even with the 250 N20 shots on them. Boat engines however are different from street engines, which tend to rev faster and higher, so if your cam and valve train are going to be set up for running north of 6000 rpm and you're running enough gear to compensate for the torque loss at street speeds, go rectangle.
WarWagon said:
http://www.maliburacing.com has a lot more guys that are into the higher-performance aspect of these cars if you're looking for better tech info...
- Status
