Engine Combo Questions

[86Cutlass383SR]

I recently had a 385 SBC EFI motor built for a specific project car which I no longer have and it's getting ready to be installed
into a differant vechicle. I need some opinions on this combo. I'd like to know if everything is well matched or anything needs attention
before dropping into my new project. Intended useage is mainly daily driven street.
Also, if someone could recommend a good cruise RPM for decent mileage so I can determine my rear tires and gear ratio.
The current motor info:

385 SBC
Heads
AFR 190 heads - older non-Eliminator style - approx 66cc chambers 2.02"/1.60" AFR valves
Comp Cams beehive valve springs - 26120-16 - 155# seat press, 377 open press, max lift .590"
Comp Cams 10° Titanium Retainers - 794-16 - for above springs
COMP Cams Pro Magnum Roller Rocker Arms - 1.52 ratio 3/8" stud
COMP Cams High Energy Hydraulic Roller Lifters - 853-16 - retrofit design

Comp Cams 280XFI HR13 Cam - hydraulic roller with 230*/236* dur @ .050" lift, 0.576 int./0.570 exh. (with 1.6 rockers - I'm running 1.52 .547" int/ .541" exh)
2000-6000 rpm range (listed as 2000-5000 but incorrect confirmed by Comp Cams)

Compression should be about 9.75 or 9.8
Deck height is about .017" down
Fel-Pro head gaskets - 1003 - .041 thick, 9.1cc compressed volume - recommended by AFR
Keith Black hypereutectic pistons - 4.040" 12cc D dish piston with 5/64" rings, floating pins
Scat Pro Stock I-Beam Connecting Rods - Forged 4340 steel, I beam, 5.7" ARP cap screws, floating pins
Scat Cast Steel Crank - 2 pc rms, 3.75" stroke, ext balance, cross-drilled mains
Milodon 18756 oil pump - Std volume - high press
FluidDampr 8" ext balanced dampener
Assembly was externally balanced with flywheel and balancer

Fuel Injection setup
1989 TPI based MAF system - stock ecm, custom harness, PCMforLess *start up* chip - will be custom tuned after running (hopefully!!!)
Lingenfelter/Accel SuperRam plenum, runners, & base - all stock unported
Holley 58mm throttle body
Ford SVO 30# injectors
stock fuel rails
stock style regulator converted to adjustable pressure
Walbro 255 lph internal pump

Ignition is with DUI stock style big cap HEI for the 89 TPI

Hedman mid-length 1 5/8" headers with full dual 2 1/2" exhaust - no cats

Transmission is going to be an Aftermarket Tremec T56 with the .62 6th gear

What would be a good cruise rpm range for this engine combo be to shoot for for best fuel mileage? I'm thinking somewhere in the neighborhood of 1600 - 2200 rpm
for 60 - 70 mph but I don't want to get it too low or too high. I need to buy gears *once* and can't afford to experiment with differant gear ratios. I know tire size will be a factor but if I can get the rpm range nailed down, then I can figure tire diameter and rear gear ratio to attain targeted rpm range.

According to Comp Cams Camquest6 this combo should be close to 490/6000 & 490/4500 on flywheel hp & torque - I'm looking to maximize torque.

Anybody see anything that is obviously a major mis-match or needs attention? Sorry for the information overload but the more info the better, right?

Ideas and feedback appreciated!!!

[86Cutlass383SR]

Anybody??? 80+ views and no comments whatsoever ...

[carguykeith]

I'm coming up with 4.11s to put you at 2,000rpm at 65mph with a 27" tall tire.

Why the 1.52:1 rocker arms instead of 1.6, seems like the 1.6s would match the motor better...

[Ron Sutton]

I looked the combo over thoroughly & think you have a good package.

But I don't have any idea on what "a good cruise rpm range for this engine combo would be for best fuel mileage?"

[86Cutlass383SR]

Thanks for the input guys !!!

carguykeith - I actually had the 1.52 rockers before I picked out the cam I have now. I didn't see much point in buying new rockers which are 1.6 rather than 1.52 for a street engine since I'm not looking for that last bit of horsepower. If they ever need replaced, then I'll get the 1.6.

Ron Sutton - I appreciate the reply. I've read a bunch of your posts.

I know this won't be the most economical motor ever built, I'm just tryin to maximize what I have. I know if you drop an engine too far down in the rpm band it's just as bad as too many rpm as far as best mileage is concerned. Is 1600 - 1800 too low or is 2000 - 2400 rpm too high *for this combo* is basically what I'm wondering about. Once I get the rpm range nailed down, then I can determine my rear tire size and gear ratio to hit that desired rpm range.

[Ron Sutton]

I surely don't know where it's most efficient at. That is outside of my wheel house.

Maybe someone else on here knows ... and we'll keep this thread going until they chime in.

[BuzzKillian]

You have to remember you are not going to accelerate well from a cruise rpm. My RPM at 65 is like 1600-1700. (3:73, 0.5 6th, 26.6D tire). That being said, your mileage should still be decent at just a tick above idle. LOL

[86Cutlass383SR]

That's about what I was thinking but wasn't sure. Thanks for the input Mike.

I've previously run this 6 speed but with a different engine combo. I know the acceleration won't be earth moving in 6th gear, that's why there are 5 others ... LoL

[BuzzKillian]

The problem you could run into though, is lugging the engine at cruise, could make it buck a little. My brother put his bigger cam in his 455 Buick with a TKO 5 speed and isn't real happy with with the occasional bucking. (He's running a Holley TBI)

[86Cutlass383SR]

Yeah that's something I'm trying to avoid. A guy I knew years ago had a fairly big cam in a Mustang with a T5 and anything below 60 mph it would start chuggin & luggin ...