i have a 4150 i purchased used from a 500hp carb engine. i did not know its condition so i decided to go through it. anyways it all looked really good. both metering blocks were very clean. the floats and bowls were also very good. i still gave them a good cleaning but in my rebuild kit i have 2 new power valves. the one that was in it looked fine. it has two holes on the inside base and such.... but the two supplied in the kit have four holes in the base and the brass tips are larger in circumfrence. one has a stiffer spring and one has a softer sping. should i just use the one with the similar spring rate or just re-install my old one with the supplied gasket. my current jet sizes are 80 and 92. i want to run a little rich to avoid problems. also my old setup was a factory 502 mag. and my new holley has an electric choke. what is the best circuit to tie into. just a recap i have a 502 gen 5 it was a 502 mag. i have a 500efi cam in it. the factory heads which are gasket matched and have the rough edges knocked down. factory displacement. dart intake off of a 500hp and the holley off of a 500hp. i had sopke with griff and he said a good starting point would be 78 and 90. not saying he is wrong or anything just thought i would ask around too. griff is my go to guy but since i was starting a thread; what the hell. also where is a good starting setting for the idle fuel/air screws. one was about 1 3/4 out and the other was about 1 out. so i know that was kinda messed up.

The stock front powervalve is 6.5. I don't what to tell you about the ones in the kit.

I wouldn't even wire the choke and would just pin it open.

You could easily stick with the 80's and 92's and go from there.

One turn out on idle screws would be a good start point.

I've had very simular BBC HP and like to run a little on the lean side. Stager jetting is one thing I have always done and will post the jet sizing - 800cfm. With what Griff mentioned is a good idea. Always start a little high and go down. I plug check constantly in normal condidtions. Temp. , humidity and so on. Try and find an average. Run the boat at your cruising speed for a about 2 to 3 minutes and imeadiately shut down. Do a plug check and repeat at WOT. Of course it is always good to check all plugs however if your in a hurry at least # 8. That is typically the hotest one. Once again I'll either post or PM you the jetting I've used and had good luck with.

Joh

and can i get rid of that mercathode deal? isnt that for saltwater? its taking up space.

If you don't leave the boat in the water for more than a day or two, you can get rid of the mercathode. Its is to prevent galvanic corrosion which is mainly caused by a very low electrical charge in the water from other boats and especially found at marinas where boats are running off shore power.

so just remove it and its circuitry? the longest it will sit in the water this year is the ozarks and it will be in a cove or something for about 6 days. other than that it is a trailer queen. its off the trailer and back on every time i go out.

Hey griff,
Just wondering what happens w/o the mercathode? It seems like all my other boats had that but can't remember. What year did they start using this and what happens w/o it. You mentioned the galvanic corrosion. Does this take place just on the outdrives etc. or gel as well? I don't remember however it seems like I recall a bit after reading your post, just want a bit more info.
thanks,
John