69gmachine 15 Report post Posted January 14, 2006 In anticipation of 500 HP, I upgraded my fuel lines to 1/2in from the fuel cell to the pump, and from the pump to a Summit fuel pressure regulator and then split to both ends of the carb. The Summit fuel pressure regulator p/n SUM-G3131, is supposed to be adjustabele from 4.5 to 9 psi. I had a modified Carter pump I bought off of ebay. It was overkill. I was unable to get the pressure below 7.5 psi. That in conjunction with too large needle and seat assemblies made the engine run way too rich. So now I'm scaling back and putting in the standard street Carter pump. I swapped the lower part of the housing onto the new pump just so it mates up with the fuel lines I've already run. I also swapped the way too big 130 needles for more practical 97s. Both are the window style. Now the only thing left to do is route the line from the pump up to the carb. Question #1: Is standard 3/8in line adequate to support 500 hp? (excursions to 5700rpm) If yes, then I will install a stock Boss 302 fuel line from the pump to the carb. I like the stealth factor. I'd really like to hear from the guys who have similar set ups. Question #2: Which direction should I be turning the adjustment screw to get the pressure to go down? I tried the Summit Tech line, but I can't get an answer. The regulator is a copy of the Holley 12-803 regulator if that helps. Thanks in advance for any advice! Share this post Link to post Share on other sites
69mach1t5 104 Report post Posted January 15, 2006 I dont know too much about that stuff but i do know turning in a regulator usually constricts flow Share this post Link to post Share on other sites
69gmachine 15 Report post Posted January 15, 2006 I slept on it and came up with a plan. Got up this morning and disassembled the pump, drilled and tapped the outlet for 3/8NPT, opened up the fuel transfer hole at the back to match the i.d. of a -8AN fitting, cleaned and then re-assembled it. This seemed to be the obvious answer as it allowed me to re-use the existing fuel lines. With the stock pump and larger -8AN inlet and outlet, I should have a HVLP fuel system not requiring a regulator, so even if I can't get it to adjust it shouldn't be an issue. I've reinstalled the pump on the engine and re-connected the fuel lines. After I get it dialed in, I may redesign the routing to mimic the Boss 302/428CJ layout only using 1/2 in lines. I took some pics of the re-worked fuel pump, but can't figure out how to add them to the post. In the attached files block there is no browse button?? Share this post Link to post Share on other sites
bswor 77 Report post Posted January 15, 2006 Did you click manage attatchments? A popup window will appear. If you did, what browser are you using? Share this post Link to post Share on other sites
69gmachine 15 Report post Posted January 16, 2006 I don't see a manage atachments option. I have a box that says attach files, but there is nothing to click on... Share this post Link to post Share on other sites
