383 LT4 dyno tune results
FWIW, my friends 383/GM846 built by a local guy who gets more hp out of LT1's than most, in an M6 Vette, put down almost identical SAE hp/tq numbers as your 846 setup, so I'd consider that number solid. His heads are home-ported LT1's copied from Lingenfelter's port job.
From your original post, I just assumed those LT4 heads were a top-of-the-heap port job, in which case the numbers are attainable with the 847 cam. My 350 with a 228 duration cam is within a couple hp of you when you factor in the A4/converter losses.
Last edited by bowtienut; Feb 22, 2015 at 02:28 PM.
Thread Starter
Teching In
Joined: Nov 2011
Posts: 8
Likes: 0
From: dfw
different dyno, i'll find the dyno sheet and post it. difference from 846 and 847 dyno #s are
0.4 more compression
ported chambers, heart shape now and unshrouded valves.
stock gear wp vs electric wp and cloyes dr chain now.
1 5/8 headers vs 1 3/4 headers now
42lbs steel fw vs 13lbs alum now
intake opened up to 58mm to match 58mm tb. same tb as before.
quench before .045 now .042
red top 30lbs inj. before bosch lll 40lbs from fic
stock opti vs deltec ign. now
think that's it
0.4 more compression
ported chambers, heart shape now and unshrouded valves.
stock gear wp vs electric wp and cloyes dr chain now.
1 5/8 headers vs 1 3/4 headers now
42lbs steel fw vs 13lbs alum now
intake opened up to 58mm to match 58mm tb. same tb as before.
quench before .045 now .042
red top 30lbs inj. before bosch lll 40lbs from fic
stock opti vs deltec ign. now
think that's it
OK, makes more sense. I mistakenly assumed the cam was the only change. Several items there that would help significantly. The flywheel change is a big dyno factor, and helps in on-track performance too.
I'm believing the numbers again
I'm believing the numbers again
