chevy

I know my question is old but i would to know,would your guy tell me
i am run lt4 hot cam in my 383 stroker engine set up with aluminum 64cc head 9.5 compressor 1.5 roller rocker, 5.7 rod .IF i change new com camshaft like CS XM 270HR-12 ,my engine is getting more power or same with the cam i had please let me know thanks

NHGuy

That's the most cam Comp says will work in a boat with normal exhaust. What is your quench?
If you take a chance and go for the 276 it will revert at idle. You will hear it gurgling too much from water in the exhaust. Then you will either ruin something, constantly be throwing in to neutral to blip the throttle, or give in and get big exhaust. If you can scrape together $1800 that's where good exhaust starts for the SBC. Then you can go to more cam.
I just finished a 9.8:1, 383 with tall pipes and lots of cam. Borrowed the cam idea from another user on here. It's the Comp 268 XFI13. Not a marine cam, but has the greater lobe separation a boat engine uses. Sounds sweet.
I haven't dunked yet. Soon though.

SB

iTrader: (1)

That Comp Cam and the Hot Cam are very similar. Intake duration is the same and the Hot Cam has a little more exhaust duration. Lift is close. I would not expect any noticeable power difference between the two.

Comp XM 270HR-12 Duration at 050 inch Lift: 218 int./224 exh. // 112 LSA // .495", .503" w/ 1.5 rockers
GM Hot Cam HR Duration at 050 inch Lift: 218 int./228 exh. // 112 LSA // .492", .492" w/ 1.5 rockers

HFT or HR ?

I am using the HR in a mild 350 w/ Eddie Marine exhaust
268XFI HR13
Duration at 050 inch Lift: 218 int./224 exh. // 113LSA // .570", .565" w/ 1.6 rockers (.534" , .530" w/ 1.5 rockers)

The 268XFI H13 Flat Tappet
Duration at 050 inch Lift: 224 int./231 exh. // 113LSA // .520", .515" w/ 1.5 rockers

Edit in: The Comp XFI lobes are very, very agressive. Therefore when helping someone spec an engine, I usually don't suggest them, just in case. I have one because I wanted to try one and I only have to deal with myself. LOL.

The XM's are tried and true, and there sbc extreme energy lobes are pretty radical in of themselves...but very proven.