Tim Burgess

I'm trying to get a '90 truck which came with a 5.7 & TBI system (1227747 ECM)
to work with a Chev ZZZ crate motor - which is a 350, as well, but has a
GM ZZZ (10134334) cam which has 0.480" lift, 235 degrees duration @ 0.050 &
336 degrees duration @ 0.004", for both int & exh. This is the first TBI
system I've worked on & so far I've tried just increasing the target idle
to 1000 rpm & also increasing the target idle to 1000 rpm & leaning out
(reducing) the two VE tables by 30%, but the thing does not want to run
unless I give it lots of base advance at the distributor. From the HC & CO
readings, it actually appeared to run lean, so I'm going to try & increase
the VE tables by 15% & see what happens. Any recommendations on what to
modify, or am I doomed in trying to get this thing to run with that cam in
there? The VE tables only go to 3200 rpm & the spark tables only go to
3600 rpm, so I'm wondering if this ECM is really capable of running this
motor......

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph

fast_broker

iTrader: (1)

You can't just change things randomly and hope for the best. DOwnload the WINALDL program from this site and get some BLM fuel numbers and go from there. That is an old engine and that cam is pretty EFI UNfriendly, IMO. It will be a lot of work and you'd be better off buying a newer ZZ3/4 roller cam to use EFI with.