L28 Swap into 73 240z help!

[busted240]

I have a 73 240z in which I removed the L24 and dropped in a L28 n42/n42 with n36 intake and 3 screw round top SU's. Car ran good before no problems. I dropped in only the head and block no accessories, kept the L24 distributor, coil, starter and alternator.

Now, when I drive the car it will break up once it hits about 4,000 rpm's. I can not get it to rev past it pretty much falls on its face. I have gaped the NGK plugs at .032 and that seems to be the best for the car. It runs great until it hits 4K then it just won't go. I checked the battery voltage it is 12.7 with the car running. I have tried adding and removing fuel at the carbs to no avail.

Is there anything else I can try? I am really eager to get it going but I can not figure this out. Also, I am going to be getting a 60 amp alternator for a 81-83 z and use the MSA adapter plug to install it. Any other suggestions are appreciated.

Thanks!

[Carl Beck]

The first thing I would check for - is restricted fuel supply. Change the fuel filter, then put a fuel pressure guage in-line with the Carb.'s. Second, would be the SU Float levels.. Pretty easy to rule out Carb/Fuel problems first - then move on to ignition problems. You didn't say where you got the SU's.. nor did you indicate what condition they were in. Did they run fine on the L24 to begin with?

FWIW,

Carl B.

[madkaw]

Check your mechanical advance assembly for freedom of movement in the dizzy.

[busted240]

Everything came off the l24 and were in working condition. I will need to put a fuel pressure gauge inline to verify it is getting enough fuel. The car a were rebuild prior to running them on the L24 but that was about 2 years ago.

[busted240]

Figured out the problem. Alternator was not charging fully so it was having breakup at higher rpms. New 60amp 280zx alt fixed everything she runs beautifully again.

[madkaw]

I thought 12.7 was low. You should see 14+ volts running