EFI Conversion on a 76 PCM 351W

Also on the PCM exhaust the back water port is blocked and the front port is open.   However since the O2 sensor needs to be on the front (no room on back) this means that both the back and front port are blocked, since the riser block water port is blocked at the O2 sense.  So 33% loss in cooling but the only way it will work.

Most of the EFI systems do not like large camshafts, his note says he has 261/275 duration but does not list at what lift, that cam is either fairly mild or pretty wild depending.  I understand the newer systems are better than the older systems for large cams.

swaterca wrote: Sorry not trying to hide anything. Rebuilt engine Al heads 175cc 62cc.  Intake valve 2.02 in Exhaust valve 1.60in CAM           Intake    Exhaust Gross Lift    0.494      0.500 Duration     261         275 11:1 Compression. Just cannot tune the Holley 650, so looking at EFI.

swaterca wrote: Is the part below for a PCM 351W? Thank you

I used the VP and just drilled the holes a little bigger. Still using the same O2 sensor. Have about 110 hours on it now. I also upgraded my distributor right after the EFI so cannot honestly say which made the biggest difference. Starts and runs like a new boat and I burn general gas (87) and have not tweaked it at all.

swaterca wrote: Sorry did you buy the riser blocks?

welcome to the world of fuel injection, I'm happy to hear that you did not get scared by all the comments fro our carburetor fans.
Peter

I saw one of the rocker crawler guys used something similar to this linkage to not have such a hard out of the gate throttle with all 4 butterfly's open..https://www.efisystempro.com/sniper-efi-progressive-linkage-kit

I don't know either been trying to figure it out. I think my thermostat may be sticking (full open). I will know better after the weekend. Never worried that much about temp before as long as it was not hot.

Good day on the lake (6/4/2020) and 160 is hard in my boat. I have to run about 3400 for 10 mins to get 160 or greater (no skiers today). It starts well (better than carb) but is still working on cold idle. IAC is working to hard but EFI table is not complete. Also, little stubble from neutral to forward/reverse. I have to advance that fuel curve so it does not stubble. Once in gear, best throttle response I have ever had (full to idle or idle to full). I do have to adjust the carb spring as a little too strong and rolls back the tach/speed I set. My feeling is 15-25 hours and should be running like a new boat.

So review so far:

cost
ease of installation
performance

I have read a lot about O2 sensors going bad so the jury is out on that piece of equipment.

John!

My regrets missing your response,! it must have rolled under my view back in March!

a few of us have spent lots to time in 454 boats and hearing them sing for a long tome,

so a 15 pith prop is leaving a lot on the table. I know you have endurance in mind, but just be aware there is a point of diminishing returns and nothing is free,.

RPMs itself wont hurt it..

Consider this....pick any loading, speed etc.the same amount energy had to get expended over time to do the same amount of work whether you go high rpm or low rpms.

In the low rpm high pitch example, this means fewer power pulses per distance traveled, however each power pulse has to have more energy. therefore lower manifold vacuum, and higher side loads on the pistons.   

Also, there is a fixed power delivery available at each rpm.   a 390HP engine 5000 may only have 230 available to you at 3600 rpm, that just wont pull 4-5 footers well.

higher pitch and high rippems means less energy needed per power pulse, higher manifold vacuum, and more power available if you give it more throttle, read responsiveness.
it really doesn't same much fuel and isnt that hard on the engine.. One could argue easier.

I think efi wont fix any dullness, it a gearing issue.

EFI wont give you 400 hp at 3600 to pull 4-5 footers. Only forced induction can do that.

let her rip!

we can consult on the carb issues

So Tom,

You're sayin 3600 RPM Bogus??

Surely the Wolfpack is way ahead of me!

https://www.google.com/search?q=wolfpack+barefoot+boat&sxsrf=ALeKk02IifvIE1OWcGjz0eCMB4v9LHmg3g:1584828676751&tbm=isch&source=iu&ictx=1&fir=n_Rf8EM69el31M%253A%252C6wrMasVmayWIIM%252C_&vet=1&usg=AI4_-kSasx9ZwPVnJLQR6le6AZB62rHknQ&sa=X&ved=2ahUKEwi4z7ryyqzoAhW3lHIEHbUQBY8Q9QEwCXoECAcQBQ#imgrc=n_Rf8EM69el31M:

Enlighten Me!!

John