baseline tune-up 6-71 blown 355 Chev

If anybody could help me out here, it would be appreciated....Been a while since I ran a blower. I need a baseline conservative tune-up for my BDS non-stripped 671-blown 355 sbc Chev in an RED. Static compression is 10:7:1, straight-up - no overdrive (yet) Hilborn #1 6.5gpm pump, 2 speed 1.76 glide, 1750 lbs wet, 280/290 .669/.637 112 lobe sep cam, MSD10+. well ported Bowtie 2.02 iron heads, 4:11 gear, 33" tire. Right now the jetting is 40/40/42/43 front to back ( hat only ) and the pill is 55. I plan on using a hi-speed by-pass as well (or do I even need it with the pump capacity near max ??) Spud says the #1 pump will work, but we're using 80% capacity so when we step it up we'll need to go to an Enderle 600 pump, but for now I just want to get it down the track - not set on "kill"
Sure would appreciate any assistance.
Thanks ITA!
Phil

 

Spud's tuneup calculator would be my first stop

http://fuelinjectionent.com/tuneup.htm

 

My first advice is to PAY a fuel injection guy of your choice for flowing your system and giving you a starting point---------- that being said I assume you are running alcohol with the 10.7 compression----------- those hat nozzles are too small, and I would not run a high speed until I ran without it first ---------------

 

First, I don't think your nozzles are too small, a small motor doesn't flow as much as a large motor and the smaller nozzles will keep fuel pressure higher.

With your current setup, I would use a .090 main pill and not use the hi-speed for now and set your bv leak down around 78% to start and see how it idles.

Good luck

 

Fuel

We run a simualr setup,, I would take the nozzles to 42, 43 , 45 , 48
81 pill 52 in HS @ 35 psi, launch @ 1600rpm.
our engine has 11.5 -1 comp RHS Iron heads, o-ringed heads & block, 504 lift cam, 411 gears, converter unknown, 225wb two pice car 1600lbs, we run 7.20,s @ 2800ft as long as the pressure is there it should run good. Nozzle area has to be within a certain range to get enough fuel in it in the first 100ft. our car has 1.09 60ft times leaving @ 1600 rpm. Our trans is a powerglide stock case, stock drum, stock output, HD input, kevlar band. No trans brake. Service your fuel system correctly and you will have good luck, neglect the fuel system and all the gremlins will grow.

 

Thanks for your replies

The advice seems to be all over the board. I inputted my engine data, including existing nozzles 40/40/42/43 and Spud's computerized recommendation is #55, which is what the bv came with. I think I will have the system completely flowed front to back - and I'll see what we're dealing with.
Thanks all for the advice

 

i ran the same set up years ago 8.050 hat nozzles hilborn -1 pump mine was a 355 brodix -11 heads standard littlefield 6-71 pill was .040 to .080 depending on air 32 max timing had a super mag 5 i built a 362 ci motor with a 10-71 same fuel system ran a blank pill when D/A was 1000 or less

the 6-71 355 went 8.01 with PG in 2800lb door car and 7.70's with 4 speed lenco

 

Senior Moments,

I would start by replacing the Hilborn 150-1 fuel pump. At 10:1 CR I can only assume that you are using alcohol. If that is the case then you will be using 105% pumps capability. As others have suggested sign at Fuel Injection Enterprise so that you can use Spud's tune up calculator. It will take some time to establish a mean tune up. By mean I'm referring to a tune up that you can use a baseline. Watch your oil dilution and the first 3-4 threads on your plugs. You cannot read the plugs in the same way that you would with gas. When the first 3 threads start to blister then you are in the zone. If you miss the zone then you will be reading your pistons. 10:1 CR is a fairly safe set up for a new tuner but, 11:5 to 12:1 will make more power. Oh yeah, watch your main bearing caps. If you are not spot on the tune up then the main bearing caps will start to walk and it will ruin your block and crankshaft.

Ron