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Originally Posted by TomZ
(Post 4654605)
Answers to your questions.... 1. Run an electric fuel pump. It doesn’t need to be anything fancy. Carter has one that should work well: https://www.jegs.com/i/Carter/180/P4...SABEgKHtPD_BwE 2. You’ll need a 1-piece seal flywheel. Check in the swap shop or post in the parts wanted section. Easy to find. 3. The factory valves are fine. Changes are really needed when you’re looking at supercharging, etc. 4. I’m assuming you have the coupler that bolts to the crank. If you do, it’ll need to be replaced to match. If yours is the style that bolts to the flywheel itself, check it for signs of twist or a breakdown of the rubber. The small block coupler is pretty strong. They tend to go bad from misalignment. Good of luck with the build! Keep this thread updated. Also, I have the following springs https://www.alexsparts.com/valve-spr...ssure-vsk4h50/ will these work with the LT4 hotcam? Is there a more aggressive cam to use than the LT4 that will make more power? I believe comp cams makes a few "xtreme marine" cams that have pretty aggressive lifts/duration, that's what I used in my last build and I loved the sound/power (that cam was flat tappet) and I'm pretty sure since I'm going roller this time around I can get a little more aggressive. Also, should I stilck with 1.5 Rockers or step up to 1.6? Since the motor will be out, I'm interested in making as much reliable power as possible out of the setup before popping it back in. Thanks in advance! |
The hot cam and spring combo mentioned is what I’m recommending. I had great performance with this set up considering what it was. I wouldn’t deviate much. On the Vortex heads you will need to have the valve guides cut down if using another spring and retainer combination. At minimum you would need to measure for clearance, but most of the time they’re too close on anything above .490. . The yellow GM Z06 spring and Comp beehive retainers have a better fit for clearance at the valve guide when using a 1.5 rocker. In my case there was plenty of room going this route. **If you use the 1.6 rocker, you’ll need to cut the guides down for sure. |
Originally Posted by TomZ
(Post 4654767)
The hot cam and spring combo mentioned is what I’m recommending. I had great performance with this set up considering what it was. I wouldn’t deviate much. On the Vortex heads you will need to have the valve guides cut down if using another spring and retainer combination. At minimum you would need to measure for clearance, but most of the time they’re too close on anything above .490. . The yellow GM Z06 spring and Comp beehive retainers have a better fit for clearance at the valve guide when using a 1.5 rocker. In my case there was plenty of room going this route. **If you use the 1.6 rocker, you’ll need to cut the guides down for sure. Thanks for all of your guidance in this thread! TomZ, I ended up going the route you suggested, ordering a oem, new, vortec 5.7 and I ended up going with the comp XM270HR cam COMP Cams: Xtreme Marine™, XM270HR <br> Inboard/Outboard Pleasure Boats, has Good Idle Another question.. I'm a bit unclear on what all I need to swap in order to put this Vortec engine into my boat which had an 86 model Merc 260 in it? I've read different things on the flywheel, coupler, starter, manifolds, water pump, etc. needing to be changed over to a different style to fit. I've also read that in 1986 GM switched the SBC to the 1 piece rear seal and the flywheel and coupler is the same as on the Vortec's and will bolt right on. Can anyone shed light, or a link ,on what I need to do to make this engine fit? Would like to go ahead and have all parts on hand to make the swap. Thanks! |
Originally Posted by 1986Scarab1
(Post 4672544)
Gentlemen,
Thanks for all of your guidance in this thread! TomZ, I ended up going the route you suggested, ordering a oem, new, vortec 5.7 and I ended up going with the comp XM270HR cam COMP Cams: Xtreme Marine™, XM270HR <br> Inboard/Outboard Pleasure Boats, has Good Idle Another question.. I'm a bit unclear on what all I need to swap in order to put this Vortec engine into my boat which had an 86 model Merc 260 in it? I've read different things on the flywheel, coupler, starter, manifolds, water pump, etc. needing to be changed over to a different style to fit. I've also read that in 1986 GM switched the SBC to the 1 piece rear seal and the flywheel and coupler is the same as on the Vortec's and will bolt right on. Can anyone shed light, or a link ,on what I need to do to make this engine fit? Would like to go ahead and have all parts on hand to make the swap. Thanks! |
Originally Posted by Paxtonspeed
(Post 4672548)
Just need a compatible flywheel with the one piece rear main seal crank flange. Everything else should bolt right up.
Music to my ears!! I think the flywheel I have is the one piece so I should be good... |
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