DragCat Posted October 10, 2019 Share Posted October 10, 2019 Not sure if this is the right thread or is should have gone in electrical, oh well. I'm getting my ducks in a row for the winter engine swap and a few people have said I should upgrade to electric fuel pump vs the mechanical. So while i'm not 100% on board I thought i'd at least ask the pros. My first question is all the electric pumps have 2 ports, not like my current mechanical that has 3. So how do you re-plumb for the lost port? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 10, 2019 Share Posted October 10, 2019 Do you want an electric fuel pump? Do you need one? When you say 2 port, do you mean one in and one out or 2 out from one? Are you talking about the pump itself or the external regulator? What combo are you planning to run? I have a mechanical fuel pump on my 496 with 1/2 fuel line from the tank to the carb and have plenty of fuel and pressure. And yes there is a difference. Lol I just didn't want a noisy electric pump anymore. They all make noise.. lolol oh well, guess I'm getting old. 🤔 Quote Link to comment Share on other sites More sharing options...
DragCat Posted October 10, 2019 Author Share Posted October 10, 2019 Laughing, no I don't want one. But i'm trying not to be stubborn in my old age that I don't listen to suggestions 😮 I'd rather NOT do electrical, just another troubleshooting point of failure IMHO. Just figured someone has done it and will give the pro's and con's. I'll put you in the no column Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 10, 2019 Share Posted October 10, 2019 I have done both and they both have their pros and cons. You haven't mentioned what your swap for the winter is. That could help in making better suggestions. Quote Link to comment Share on other sites More sharing options...
DragCat Posted October 11, 2019 Author Share Posted October 11, 2019 I'm dropping in a GM Crate 502. I'm still on the learning curve of the Monte's so I'm not really sure I understand why there are 3 ports on my existing mechanical fuel pump. Also looking at an old OPGI catalog it looks like the holly GM high performance mechanical fuel pump only has 2 ports. So I'm wondering on each difference what has to be modified changed in either scenario. On a side note, from the prior post where Hemmings dropped a GM crate in a Chevelle, I know if I stay mechanical I'll need to get a "special" fuel pump push rod. Quote Link to comment Share on other sites More sharing options...
502ci Posted October 11, 2019 Share Posted October 11, 2019 Does your crate 502 have the provisions for a mechanical pump? I know on my crate 502 there were none so I had no choice but to go electric. Been so long I do not remember the original pump...but doesn't it have an inlet, an outlet to the carb, and the third one was a return to the tank? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 11, 2019 Share Posted October 11, 2019 502ci is correct with the 3 lines on the factory mechanical pump. He is also correct with checking if your block has the mechanical pump provisions. Although I believe GM has added them to the newer 502 blocks. I have the biggest Holley fuel pump (gph) they make without having to use an external pressure regulator on my 496. Works great. Only has 2 lines, one in and one out. No "special" fuel pump rod. Quote Link to comment Share on other sites More sharing options...
DragCat Posted October 11, 2019 Author Share Posted October 11, 2019 Yes the new 502's do have the provision for adding a mechanical fuel pump. So what do I do with the return line if I go to a 2 port mechanical or electric ? What i'm saying is I don't understand the return line configuration or how do I delete it from the system. From the Hemmings Chevelle article, not word for word but a summary, with the new crate motors and their roller type camshaft if you use a mechanical fuel pump you need to upgrade the push rod (bronze tip for example. I'll see if I can find the specific article. Found it https://www.hemmings.com/blog/article/surgery-without-scars-3/ Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 11, 2019 Share Posted October 11, 2019 Ahhhh ok. With a roller cam you would use a bronze tip fuel pump rod as not to wear the cam out for the fuel pump. As far as the return line, you could leave it alone, (open), or cap it if you have a vented gas cap. I just left mine open. No fumes or gas smell. And I store the car in a garage. If you went with an electric pump, you could use the line as a return line from the regulator if you get that type of regulator. Supposed to keep the pump running cooler by having a return line. Quote Link to comment Share on other sites More sharing options...
DragCat Posted October 11, 2019 Author Share Posted October 11, 2019 Thanks Thomas. I did hear back from the supplier and the holly mechanical pump is the 3 port version. Another member PM'd me and said his holly recommended upgrading to a 3/8 line not the normal 5/16 so I may have to do that. Thanks for the answer to my plumbing concern question. Now I feel comfortable if I were to go electric or 2 port mechanical. I'm trying not to upgrade/change too much with the engine swap so other than complete part failure it ran before so no reason it shouldn't run now. As an old guy the main reason I still like carburated engines, air, fuel and spark the thing should run. The old KISS principle. Appreciate all the comments, it was a good day as I learned something new about my Monte , cheers Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 11, 2019 Share Posted October 11, 2019 You may want to think the fuel line size over. I know how my 496 loves fuel so I can say the 502 will also. Lolol I used a RobMC 1/2 fuel tank sender that I installed into the tank, then ran cloth 1/2 fuel line up to the pump following the stock line until it went into the frame. Had to remove the stock 3/8 line for the 1/2 to fit. Then the same line from the pump, with a micron filter to the carb. I used the "cloth" line due to it being much easier to bend and install. Like you I like to keep things as KISS as possible. Lol plus I don't like doing things twice. Lol Also, check your line size, I believe all Montes had 3/8 fuel line. Small and big block. Quote Link to comment Share on other sites More sharing options...
DragCat Posted October 11, 2019 Author Share Posted October 11, 2019 Thanks, I'll double check the existing fuel lines. I just assumed 5/16 to the pump. Of course if the holly or crate "suggests" 1/2 I'll do that. I had anticipated some plumbing so I had 2 O'Reily $$ coupons and bought some 3/8 and 5/16 tubing. I still have the receipts so I can swap'm if needed. Damn thats a clean engine compartment, I thought mince was clean. Quote Link to comment Share on other sites More sharing options...
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