rpm's and performance

[bill mason]

I have a modified 260 and a 03 280 block with 260 electronics. For years I thought I had an inherent problem as neither of these powerheads would ever pull ANY prop over 8700 rpms. I have changed out EVERY piece on both blocks. I keep reading a lot of you are pulling these engines over 9000 rpm. Well I found out something yesterday. NOTHING IS WRONG WITH EITHER OF THESE POWERHEADS!! I have a new complete 280 and yesterday I put an an unlimited ECM and ran a 24 ET. This engine pulled almost same rpms as the other two do. I really find it hard to believe anyone is pulling any more rpms running a 2003 Alliosn?? The one thing that is odd is that the new 280 will pull a 28ET 7300-7500 rpm but neither of the other two will pull it over about 6800 rpms (and one of the powerheads is the same block)? Any of you guys that have different results?? I have three of them that tell me no?

[pappa pete]

have had the same problem with a merc motor one problem was the timing advance was sticking and not advancing enough and the other was a fuel line was bad on the inside and causing restriction hope this helps just a shade tree mechanic Pete :D

[wideglide55]

I think 8700 is very respectable rpm if its hooked up,ain't it fast enough for you yet?

[bill mason]

8700 rpms from all three power heads to me proves that is what can be expected from my set up. As I said I keep reading about several guys turning well over 9 grand with small props and pulling large props (like 28 ets) 8 grand. I always thought something was wrong with my power heads but now that I am calling anyone out I don't hear those figures any longer. It just took a long time to verify that yes 8700 is respectable. thx guys

[steve]

Port timing will not be identical on every block, nor will someother factors. Sometimes there are a variety of little differences in the same species of motor that make one run stronger then the rest. Also the various year of the XB2003 can make a difference as can the setup. Remind me to email you a local guys info . He's running a 28ET to a 7000 limiter and I know he can spin higher. He's got a 260 with a few mods we did for him.

[action280]

i have two 280's..one pulls a 28 cleaver to 7300 the other one hits the limiter at 7700 with the 28, or even a 30 and pulls a 32 to 7500..same boat, same set up.