1994 90hp X-flow

[1FASTLASER]

Did a searcg and am not finding what I need to know. I have been told that without getting into alot of reporting this engine that if I cut the heads and add the 1 3/8 crabs that I will noticew a good amount of difference. I dont mind paying for the higher octane. I just need to carry a slightly heavier boat a little better. How much on the heads and still run pump 93 gas and will the 1 3/8 carbs be ok without reporting. After doing these swaps and mods do I need to do anything to the tuner. I am not real familiar with OMC so I need ya'lls input on this.

[bw1969]

Cutting your heads won't do much good. You will need heads from a 140 xflow (not sure of the part #s) they have a better combustion chamber shape. You will also need to re-jet the 1 3/8 carbs for your application. Without porting I'm not sure you would benefit much from the larger carbs, might want to goto 1 1/4 instead.

[terry taylor]

HI. Yes good point, port size and port mapping is how well and when an engine breathes better breathing more power thanks.

[Riverman]

The best V4 crossflow heads are from a 73 135, P/Ns 317848 & 317849. But you can't have any, they are all MINE! :D :D

[1FASTLASER]

The best V4 crossflow heads are from a 73 135, P/Ns 317848 & 317849. But you can't have any, they are all MINE! :D :D


Ok with these heads ( Iam sure that I can dig up a set around here) I can bolt them on and get SOME perormance. I am just trying to carry the boat a little better. I dont want to sacrice longevity of the engine. Thanks for the part #'s. The search has now started. I already have some carbs located, just didnt know whether I needed the 1 3/8 or not. If memory serves me right I have the 1 5/16 on them right now. It does ok with the setup I have but as always am trying to get a little more.

[EMDSAPMGR]

I'd stay with your 1 5/16 carbs. You may find you have to fiddle with the larger carbs to get them to work, esp check the length of the throttle shafts to make sure they are the right length. Add 4 of the intake filler blocks, p/n 322684. They are nla, but are still around if you look. As good as the 135 heads are, they don't have the coil supports, you will have to modify/make something for the coils. optional heads: 79 140 322865/864, or later 140 326503/502. A set of composite reeds will help in overall smoothness and throttle response. You might even pick up a few hundred rpm.

[Forkin' Crazy]

You gonna put that on your Laser? Better change your name to 1SLOWLASER... :eek:

;)

Or put a V6 on it. :)

Never seen reeds pick up rpms. They are better digested by the motor should one break off though!

[76baja18ft]

The best V4 crossflow heads are from a 73 135, P/Ns 317848 & 317849. But you can't have any, they are all MINE! :D :D

they arent all yours..lol:eek: .. i got a set laying on my work bench..:)

[Riverman]

they arent all yours..lol:eek: .. i got a set laying on my work bench..:)Are they for sale?

[76baja18ft]

Are they for sale?

i was gonna sell them at one time.. but decided to keep them...:rolleyes:

[EMDSAPMGR]

I don't think the V4 engines ever came with a 1 3/8 carb. You would have to waste inordinate time to get them to work. If you do, the extra airflow will compromise your hole shot. The 1 5/16 is the largest they ever put on, and they work great, so stay with them. Heads will up compression 10-15 lbs. Not a lot, but worth the effort for a bolt on part. Also, you'll get 5 hp out of the intake filler blocks. You can fill the top hole of the water intake on the lower unit. Run with the bottom 3 holes open. Then raise the engine on the boat another hole and get a good cupped stainless. That prop is used to running higher out of the water. It will give you another 1/2 mph. Your engine is what they call a "low port" engine. It will rev up to around 5700 or so, then run out of breathing capability. The 140 engines were ported higher and will rev slightly higher. I've ported the intake and exhaust on a number of these low ports and it gets the portin close to the 140 ports. It's worth top end, should you ever take the engine down for overhaul. One other thing, prop related. A good stainless prop like a raker, will help lift the bow. Loaded with gear and an alum prop will cause the bow to plow and loose speed. Keep the bow up: less wetter surface= more speed. The bolt on parts are easy to do, worth the effort and don't compromise relability at all. One other thing, if you go for the high comp heads, plan on running premium gas. Good luck with your project. I could not get this message to reply to your other email....

[1FASTLASER]

I really appreciate the time you have taken to explain to me what I need to do. Now that I have some idea of what needs to happen time for me to get the wrenches out. Have already placed a call to see what heads are still left at a friends of mines house. The current prop (Raker) will be shipped out tommorrow to get bal./blueprinted. Ifn the engine takes a crap or I get bored I will remeber the porting advise. Again thank you.

[76baja18ft]

I don't think the V4 engines ever came with a 1 3/8 carb.

Really?.:eek: .. cause i have a set of v4 1 3/8th carbs...:rolleyes:
have had them several years

[1FASTLASER]

You gonna put that on your Laser? Better change your name to 1SLOWLASER... :eek:

;)

Or put a V6 on it. :)

Never seen reeds pick up rpms. They are better digested by the motor should one break off though!

Forkin I do beleive ya know me well enough to know that aint no SLOMC going there. There's only room for 1 MOTA back there...............

THE BLACK BEOTCH

[Paul Vaillancourt]

Sorry, I am no expert but..... I have a 1978 140 crossflow that came with the 1 3/8" carbs stock. I have used them on my 1973 135 with no modifications.




I don't think the V4 engines ever came with a 1 3/8 carb. You would have to waste inordinate time to get them to work. If you do, the extra airflow will compromise your hole shot. The 1 5/16 is the largest they ever put on, and they work great, so stay with them. Heads will up compression 10-15 lbs. Not a lot, but worth the effort for a bolt on part. Also, you'll get 5 hp out of the intake filler blocks. You can fill the top hole of the water intake on the lower unit. Run with the bottom 3 holes open. Then raise the engine on the boat another hole and get a good cupped stainless. That prop is used to running higher out of the water. It will give you another 1/2 mph. Your engine is what they call a "low port" engine. It will rev up to around 5700 or so, then run out of breathing capability. The 140 engines were ported higher and will rev slightly higher. I've ported the intake and exhaust on a number of these low ports and it gets the portin close to the 140 ports. It's worth top end, should you ever take the engine down for overhaul. One other thing, prop related. A good stainless prop like a raker, will help lift the bow. Loaded with gear and an alum prop will cause the bow to plow and loose speed. Keep the bow up: less wetter surface= more speed. The bolt on parts are easy to do, worth the effort and don't compromise relability at all. One other thing, if you go for the high comp heads, plan on running premium gas. Good luck with your project. I could not get this message to reply to your other email....

[Forkin' Crazy]

Forkin I do beleive ya know me well enough to know that aint no SLOMC going there. There's only room for 1 MOTA back there...............

THE BLACK BEOTCH

I know dude! :D Just yankin' yo chain! :D You bleed black and can't help it!!! http://i120.photobucket.com/albums/o168/forkincrazy/laughing.gif

[Riverman]

I don't think the V4 engines ever came with a 1 3/8 carb. You would have to waste inordinate time to get them to work. If you do, the extra airflow will compromise your hole shot.

1 3/8 carbs work great on a crossflow, and they did come with them for several years.

[EMDSAPMGR]

Paul, you are absolutely correct. Some of the early 140 crossflows did come with 1 3/8" carbs.

[930turbo]

My '78 140 has 1 3/8 carbs.