Ct525
11-15-2010, 01:33 PM
#1
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Ct525 --------------------------------------------------------------------------------
I have CT525 in a dirt latemodel, it has a *****'s E-85 carb & on *****'s Chassis Dyno it made 490 RWHP. They said that was approx 600 at the flywheel.
At some tracks where we run we get a 100 pound weight break against the open motors (700+) as long as the motor still has the GM seals. when the tracks are slick it is great, but if we run a heavier track or a bigger track the weight break isnt enough.
I am thinking about breaking the seal to gain some power & giving up the weight break, where would my money be best spent, I am lookig to gain approx 75 hp .
As I understand it the crank & rods shouldnt be an issue & should handle the extra power with no modifications.
I plan on upgrading the Pistons to forged & adding some compression currently 10.7 looking to go to 12- 12.5 to1
Is there enough to be gained by porting the heads to make it worthwile?
What about Camshaft, the current cam has only .525 lift, but the driver really likes how smooth & drivable the engine is.
Currently we have the rev limiter set at 7300,if we could go to 7500 we could run more gear, but I would like to stay with hydraulic lifters.
Or should I just put a 75 hp nitrous kit on it & only use it when we need it?
Would the stock pistons handle th nitrous in limited use?
Thanks, hhc11
I have CT525 in a dirt latemodel, it has a *****'s E-85 carb & on *****'s Chassis Dyno it made 490 RWHP. They said that was approx 600 at the flywheel.
At some tracks where we run we get a 100 pound weight break against the open motors (700+) as long as the motor still has the GM seals. when the tracks are slick it is great, but if we run a heavier track or a bigger track the weight break isnt enough.
I am thinking about breaking the seal to gain some power & giving up the weight break, where would my money be best spent, I am lookig to gain approx 75 hp .
As I understand it the crank & rods shouldnt be an issue & should handle the extra power with no modifications.
I plan on upgrading the Pistons to forged & adding some compression currently 10.7 looking to go to 12- 12.5 to1
Is there enough to be gained by porting the heads to make it worthwile?
What about Camshaft, the current cam has only .525 lift, but the driver really likes how smooth & drivable the engine is.
Currently we have the rev limiter set at 7300,if we could go to 7500 we could run more gear, but I would like to stay with hydraulic lifters.
Or should I just put a 75 hp nitrous kit on it & only use it when we need it?
Would the stock pistons handle th nitrous in limited use?
Thanks, hhc11
11-17-2010, 06:17 PM
#2
Talk to someone like Wegner Automotive about porting the heads or swapping yours as a core for a set of heads that have been ported. Wegner has been doing circle track stuff for years and have some really nice LS parts- not to mention a lot of experience in Winston West and Busch Grand National Series. If they are L92/LS3 style heads on the CT525, look into offset dowling the heads in addition to running a ported casting. The intake valve centerlines on those heads are a problem where the inlet valve is shrouded due to being too close to the cylinder wall. Offset it to the exhaust side to help out this problem. Also consider porting the manifold too as this is important with any carbureted engine.
Camshaft is always worth changing. Speak to LSM Engineering on the cam. If the driver likes the manners of the camshaft now, get something with similar timing events but increase the lift as much as possible to coincide with the flow numbers of the ported head castings. Look into a Morel limited travel style lifter that should behave more consistently under constant rpm and that will be good insurance along with the added lift of a new cam.
If you choose to change pistons to increase the compression, I would also do a new set of connecting rods too. Because you are talking circle track, I would not spare any expense on the rods. Go lightweight and American. Start looking at Oliver and Crower for rods. If you are giving up the weight break and thinking of increasing the compression, you might as well go 15:1 and run with the open motors. No sense in going only halfway at 12.5:1.
Good luck!
Camshaft is always worth changing. Speak to LSM Engineering on the cam. If the driver likes the manners of the camshaft now, get something with similar timing events but increase the lift as much as possible to coincide with the flow numbers of the ported head castings. Look into a Morel limited travel style lifter that should behave more consistently under constant rpm and that will be good insurance along with the added lift of a new cam.
If you choose to change pistons to increase the compression, I would also do a new set of connecting rods too. Because you are talking circle track, I would not spare any expense on the rods. Go lightweight and American. Start looking at Oliver and Crower for rods. If you are giving up the weight break and thinking of increasing the compression, you might as well go 15:1 and run with the open motors. No sense in going only halfway at 12.5:1.
Good luck!
