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  1. Lt1z350

    4.3lx intake manifold question

    Well i just did two street tricks with the coil and the plug gap increase and added 4 mph and over 400 rpm. The manfold isnt all about hp its gaining 50 lbs in torque below 3500 rpm according to the dyno graph they sent me. Hp and tq is the same add and what ever your applying it to will go...
  2. Lt1z350

    4.3lx intake manifold question

    So got back out with just my wife and I again back to same conditions or as close as possible anyway to the first few prop tests prior to carb coil and plugs. So 2 people 1/2 tank and moderate chop not smooth at all. 46/47 mph at 4800 rpm. I checked my plugs no signs of detonation at all and...
  3. Lt1z350

    4.3lx intake manifold question

    Sorry forgot to post last results. So last time I worked on it I put new gm 43 marine plugs gaped to .045 not factory .035 the ones I pulled the ngk were more like .030. Also cleaned and threw a edelbrock kit at the carb. Set floats and idle to 19 inches vacuum 650/700 rpm. I also installed...
  4. Lt1z350

    4.3lx intake manifold question

    When I get other off I’ll do a direct compare on it all for everyone to see. Design wise it’s just newer better technology vrs what they ran when the iron intake was designed and then never changed for any of the newer motors. So the cast iron is truly 80s Marine technology and really built...
  5. Lt1z350

    4.3lx intake manifold question

    Boat was realy slow to get up on plane with that prop on it. If you just nailed it the prop cavatation was terrible so had to roll on it slow. I see your point on all that for sure why I wanted to see if cleaning up some things I could get a little more rpm from this prop as its so good and...
  6. Lt1z350

    4.3lx intake manifold question

    So here is a quick shot on edelbrock. Runners are all the way up to plenum. Stock has one open larger runner no divider to the cylinder head. This design is to build more torque proven on any v8 engine combo. It’s also taller I think 2 inches so will add to peak rpm hp. It’s a proven design just...
  7. Lt1z350

    4.3lx intake manifold question

    Mine pulled fine to 5000 rpm with the 14/19p so that tiny 15p I’d hope at least that which they do say is too many rpm. Affective range is 4500-4800 rpm. Since going to a 19p 4 blade prop I’ve lost more rpm then expected. I also tried a 13.25/24p 4 blade stainless steel as on my bass boat and it...
  8. Lt1z350

    4.3lx intake manifold question

    I did think about doing the spacer but found the edelbrock intake on amazon as a return for 280 bucks vrs 350 most places so saw that as good enough deal to just give it a try. This one I have comming is a ton different then the one I showed on the top in the pictures with the open plenum...
  9. Lt1z350

    4.3lx intake manifold question

    This thing has that thunderbolt IV on it and what I have found is a point and shoot for setting up timing. I found 8 degrees btdc if someone can verify this for me great. So as I had posted before I just added some on the water and was alot better on my last run home for the day. i couldnt get...
  10. Lt1z350

    4.3lx intake manifold question

    I did a ton of research on the vortec heads vrs this casting number on this boat. These are not the swirl port heads that cannot flow air but the heavy duty gm castings that were marine specific. They flow way better then then the earlier castings and what I found were specific to 94/95 only...
  11. Lt1z350

    4.3lx intake manifold question

    bottom end isnt the issue at all. It screams out of the hole I am actually impressed with how fast its up on plane. It struggles with higher rpm some. Changing to this 4 blade I lost 700 rpm and seems to struggle at 4300 trying to maintain top speed. To me thats something going on up top. My...
  12. Lt1z350

    4.3lx intake manifold question

    That is one of the issues on upper rpm. I am on a hustler 4 blade 14/19 now 44 mph was only 4300 rpm where the old solis 3 blade 14/19 was 45 at 5000 rpm prop was beat up pretty bad so probably a little more slip then it should have been. Hole shot is excellent on this 4 blade was poor on the 3...
  13. Lt1z350

    4.3lx intake manifold question

    Just says marine high rise but has egr which is Odd. It’s a lot taller then what’s on this boat but can see it’s dual plane.
  14. Lt1z350

    4.3lx intake manifold question

    Short runner single plane iron intake. It has a slight divider not very tall. But not a true dual plane long runner made for torque and lower rpm like this motor. I called edelbrock they claim 18 hp from the tech department. Took a 180 hp 95 down 4.3 and made 202 I guess the original intake...
  15. Lt1z350

    4.3lx intake manifold question

    Right now the holeshot is just about 3 seconds I don’t see it get any better then that. Lol it comes up so fast on this new hustler prop and lost no wot at all. But rpm is lower from 5000 rpm on the 3 blade rubex to now 4300 on this 4 blade. Same 44/45 mph depending on water conditions. So was...
  16. Lt1z350

    1989 xr4 150 that sat 3 years issues.

    So it’s coming along working on a few projects. Going to work on buttoning it up today and get drive ready and cleaned up. I ended up around 3.378 on most holes which these pistons I got were good to 3.380 by manufacturers specs. I used a 180 grit on final hone and I’m happy with how good it...
  17. Lt1z350

    94 chaparral 1930 ss with 4.3 prop help

    Here is the other thing I’m thinking on so many hp versions of the 4.3. Some better heads I know that but anything from 170 to 230 mpi. I know that in the past manufactures change to engine timing was how they got certain ratings. They do this on small engines all the time like atv/ lawn mowers...
  18. Lt1z350

    4.3lx intake manifold question

    I found some posts on this but no one says I gained x from the swap. Some are 2bb to 4bb so those don’t work. I got a 94 4.3lx non vortec heads. I see edelbrock has an intake and they claim 18 hp vrs the stock merc cast iron. I have not taken off the carb but stock looks to be open plenum...
  19. Lt1z350

    94 chaparral 1930 ss with 4.3 prop help

    I need to get a manual and see where I’m at so far on it. Plugs looked good and my guess is the guy working on this boat for him re sealed this intake and didn’t set it up right as it felt so much better with just a tiny tweak. Even idle cleaned up like he had it too low. So I’m going to find...
  20. Lt1z350

    94 chaparral 1930 ss with 4.3 prop help

    I need to go weigh this as curious now the actual weight. I think when I first looked it up I did the 1995 which shows the v8 as the motor size and that was 2500 lbs. This is a 1994 sst which I now see is a little different then 95 ss. Probably not a lot why worth going to the truck stop and...
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