What ECM changes would be needed?
Thread Starter
Racer
Joined: Aug 2004
Posts: 371
Likes: 0
From: California Missouri
What ECM changes would be needed?
I am considering buying an 85 or 86 coupe that is in need of some engine help,, I have a brandnew 355 in my garage that I was thinking about swapping in. I plan on keeping the original and getting it sorted out down the line. My question is this. My 355 has a Part Number 12-416-8 cam
Grind Number CS XM 264HR-12
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.488 0.495
Duration At 0.006 Tappet Lift 264 270
Valve Timing At 0.006
Open Close
Intake 22 62
Exhaust 69 21
These Specs Are For The Cam Installed At 110 Intake CL
Intake Exhaust
Duration At 0.05 212 218
Lobe Lift 0.325 0.33
Lobe Separation 112
this combined with edelbrock performer heads 1.6 roller rockers and stock approx 9 to 1 compression,, what would need to be done to the computer to get this engine running at its optimum. the short block of my engine is out of a 98 pickup. I would like for this to go as smoothly as possible. Any info , is greatly appreciated. I posted this in the tech section but no responses.
Grind Number CS XM 264HR-12
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.488 0.495
Duration At 0.006 Tappet Lift 264 270
Valve Timing At 0.006
Open Close
Intake 22 62
Exhaust 69 21
These Specs Are For The Cam Installed At 110 Intake CL
Intake Exhaust
Duration At 0.05 212 218
Lobe Lift 0.325 0.33
Lobe Separation 112
this combined with edelbrock performer heads 1.6 roller rockers and stock approx 9 to 1 compression,, what would need to be done to the computer to get this engine running at its optimum. the short block of my engine is out of a 98 pickup. I would like for this to go as smoothly as possible. Any info , is greatly appreciated. I posted this in the tech section but no responses.
Intermediate
Joined: Feb 2007
Posts: 28
Likes: 0
From: Joplin MO
That sounds like a mild enough combination that a mail order prom would do just fine, but you might need to step up the injector size, or at least get an adjustable regulator. I think there are people on this site that can do a mail order prom, and there are also several guys that sell chips on ebay that will burn one custom to your specs, but they will need every possible scap of info you have about the engine to get it just right. I checked into it a while back, and I was told that they can burn prety good chips if the cam you are using has less than 228 deg. dur. @ .050" lift.
BTW, I've seen guys run slightly bigger cams without changing anything else, so you could probably just put that 355 in and run all of the stock stuff with it and be okay, but it would run a lot better with a custom prom.
BTW, I've seen guys run slightly bigger cams without changing anything else, so you could probably just put that 355 in and run all of the stock stuff with it and be okay, but it would run a lot better with a custom prom.
Last edited by vettonator; Feb 22, 2007 at 01:24 PM.
Thread Starter
Racer
Joined: Aug 2004
Posts: 371
Likes: 0
From: California Missouri
Thanks for the reply!
Been kind of scarce on this one. I thought it might run o.k.,, without,, I do have a Ram Jet cam that would probably work better with the stock tune but I would rather run the bigger cam. I thought the 112 lobe separation would be big enough to tame the duration down to make it compatible.
