Sorry, the EP381 will support up to 450HP at 155LPH, that Walbro is 105LPH. I'm getting close to 435HP (according to Blue Print Dyno) so I want some wiggle room. OP may not be putting out that much so, your pump will probably work fine.
That's cool. How about its flow? Seems to me it's still not enough. When I'm running up to 90% injector duty cycle @20 PSI on WOT I'm a little Leary - I may be wrong, I just want the peace of mind I have enough pump down there. :waytogo:
For a mildly built TBI, or carbed engine, that may work. But not on a Vortec (needs 60PSI min) or a well built TBI. IIRC the EP385 is rated 155Lph @ 65PSI so, I would go with the Walbro 255LPH one to ensure enough flow.
I don't see where there's any speed limiter on the 7747 but, my EBL Flash-II can limit spark and fuel you can set to any value, even has a "Valet" limiter.
1st - fix your MAP issue. Maybe your vacuum going to the TH400 is leaking, allowing low vacuum reference to it.
Yes, normally you'd set your initial timing at 4° on a 454 but, depending on your cam and setup, you may want to go higher for startup. For example, I set my 383 to 10° with the EST...
These show the application for 5.0 and 5.7 TBI heads but, for .344" valve stem. I wonder if someone modified your heads so the bigger stem would work with bored out guides?
www.summitracing.com/parts/FEL-SS72527
https://www.summitracing.com/parts/FEL-SS72527
Edit: I used these on my Summit...
You want mandrel bent, smooth transition Y, and Stainless Steel. The JBA 2831 SY is one of those but, not cheap. When I bought mine, it was $188.99, now it's $330.45 :fca5278d:
www.summitracing.com/parts/jba-2831sy
https://www.summitracing.com/parts/jba-2831sy
He's working on a 94, they don't have post cat O2 sensors.
IMO you'd have to have a pretty wild cam to reduce vacuum sufficiently where the EGR won't work properly. I'm running a 230/236° @0.050" duration without issues - before I eliminated the EGR and went to Hiwy Lean Cruise :wink:
Edit...
A 383 stroker is 4.030" bore X 3.75" stroke or 4" X 3.80". A 4" bore by 3.75" is a 377 cu in. In all cases you need to clearance the block for the stroke and possibly bore it for new pistons, etc.
Here's some kits as an example...
Yes, I put a circle around where there's a black spot just under the iron which gave me an intermittent rough idle and shorted completely when I went through the car wash. I found it by spray some water around on the ignition system and, when I sprayed the coil, the engine died.
I would think, with the smaller 94 - 95 injectors at that pressure, it would run even better since you'll have a higher differential between boost and TB pressures but, I may be wrong.
Here's what I got out of an Accel coil after 6 Months on my 88. The engine started to die when I ran it through the car wash and idle was a little choppy. Now I'm running an AC Delco GM Genuine coil - no issues. YMMV