Port Heights

[jeffreynolds]

need some professional advice on porting 1990 2.4 fatblock for heavy basser carb motor horizontal reeds would like to keep rpm reasonable??? thanks in advance

[TB21]

need some professional advice on porting 1990 2.4 fatblock for heavy basser carb motor horizontal reeds would like to keep rpm reasonable??? thanks in advance

For a heavy bass boat leave the ports alone. Cut the heads for 145lbs. cranking pressure max. for good pump gas and work on the set-up to get your max. Good luck , TB

[Jay Smith]

I agree with TB raise the ports you'll wish it was back like it was.........

[jeffreynolds]

what can i do to increase hp other than comp. increase my motor started life as xr4 150 can i make more reasonable hp with exhaust work etc. thanks guys for your help,jeff

[TB21]

for a 2.4 on a heavy boat theres nothing gonna help as much as raising the compression , as long as you stay 140-150 psi and keep "good gas" in it you'll be fine and thats the biggest gain for the $$ , i don't know for sure but if an xr4 has that long narrow tuner you can gain a little by switching to the short 200 or bobs tuner but don't cut any in the exhaust cavity it will kill your lowend power. What kind of boat is this on? TB

[jeffreynolds]

the boat is a 18 ft sprint dual console basser advertised hull wt 1250# plus motor and gear makes for a heavy slug i have obtained a 200 tuner thanks jeff

[stan merck]

An XR4 I saw apart had much lower port heights on ex and intake than a 2.4 200 has. I would raise them to the 200's heights. I think that is what every else is saying, dont go past a 200's stock heights.

[jeffreynolds]

that is what i am saying but i dont know what the 200 port heights are i do want to be conservative because too much is a good way to ruin a good block thanks jeff

[Reese]

I have an 89 xr4...vertical reeds...14" long tuner. If you indeed have horizontal reeds and a 200 tuner there ain't much left to do.

If you haven't already installed the 200 tuner can you post any difference it makes...bottom end hole shot and top end.

Byuboyz have a very nice article on a Trex modified 2.4, although I highly doubt it would work on your boat.

Here is the link. Byuboyz 2.4 cherry

[roadkill636]

What is STOCK port heights on a 200 2.4? Im seeing all sorts of info for 2.5 but can someone post 200 2.4 heights please. Fingers tired of searching for it.

[wrechin2]

need some professional advice on porting 1990 2.4 fatblock for heavy basser carb motor horizontal reeds would like to keep rpm reasonable??? thanks in advance

I deal with heavy bass boats on a regular basis and have done several of the fat blocks and have had huge increase in power. The best was a 1990 361 ranger with a 1990 175 fat block(same as yours with different porting and carbs) and it went from 56 GPS loaded to 67 GPS loaded. BUT there was a lot of work involved as it has some behind the liner work , angled and opened the exhaust, carburetor change, and porting raised, cut heads, cut front half, stuffed front half, rod slots widened, oil injection gear filled, piston window work, finger ports widened to 1/2" and the bottom end was better and then we fuel injected it and it got stronger on bottom and runs the same on top. Here are a few pics. Just my actual experiences

[Capt.Insane-o]

Nice work!

[johnmiffco]

agree,,,,that is some nice work there,,,,
reminds me of the 80s when
used to weld cups/tubes on outside of block
from rod slots to enlarge transfer ports

[Slimm]

I made a few changes to my setup: Pulled my lower unit and midsection in order to do the exhaust modification outlined here (http://www.screamandfly.com/showthre...rd-midsections) by Talon2.5. While I had the mid off I swapped the factory tuner for a shorter bell shaped one and I cannot express how big a difference those two changes made. My boat seems to comes out of the hole at least 50% faster (and harder) and it pulls so much harder now. I can't wait for a nice day and some relief from my back so I can get out on the water and just drive..I might have to bundle up good and fluffy tomorrow morning and hit the river early and run some fuel through it all day.

I love this sport, I could read and talk about it all day and night! Funny thing, I was in Saint Louis a couple weeks ago for a band competition that my girlfriends daughter was performing in. This was our first time getting to actually spend the night together so we were pretty hyped. I woke her two or three times telling her about Merc 2.5 tricks and changes..doubt I will ever live that down. Good thing she loves it almost as much as I do.


Slimm

[TEXAS20225]

James does the best port work ive ever had done ,and he aint the only one ive used( some BIG names) , he is now my only machine shop man his work is always super clean and his boring, decking, and other assorted goodies produces great customer satisfaction, they do not pop,