Performance parts for 79 135hp?

[Lk40hp]

I am just curious if there are any parts I can get to squeeze in a few more mph out of my 79 135hp....
I know props can, but is there anything other than props?

 

[nwcove]

Re: Performance parts for 79 135hp?

other than making sure the motor is tuned up and running at its best, aside from props, motor height and trim is about all you can do. jmo ( unless you make your boat lighter of course, which would take you back to props and motor height on the transom.)

 

[boobie]

Re: Performance parts for 79 135hp?

Do what Nwcove says. If you start messing with the mtr itself the cost isn't worth it.

 

[Chinewalker]

Re: Performance parts for 79 135hp?

No such animal as a 1979 135. As it was, the 135 was ALREADY a hopped up version of earlier V4s, with tuned exhaust, bigger carbs, aggressive intake and exhaust porting. As noted above, your best bet is to make sure you're getting all 135 ponies - it is around 40 years old (last year for the 135 was 1976), and unless it's been freshly rebuilt, it's likely on the tired side.

 

[emdsapmgr]

Re: Performance parts for 79 135hp?

The later 140 crossflow engine has a couple of differences. There is an exhaust cutout at the bottom of the exhaust chest of the block. Also, it had the rubber intake stuffers. Guess that accounted for the 5 hp, but my guess it that it was a little more. Agree, work on your setup (engine height and prop) to be sure you get the most out of your engine. Your engine was crank-rated hp. Around 1986 they changed the hp ratings to propshaft hp.

 

[V153]

Re: Performance parts for 79 135hp?

What's been posted about the factory intake & exhaust mods is correct. Make sure you have the 1 5/16" carbs too, vs 1 3/16". One thing that wasn't mentioned is hi-comp heads. If the motor is in good condition & doesn't already have them installed, you can easily add high compression heads. (See head on right in pic.) 20 bolts & a pair of gaskets et voila! A marked improvement in performance. Part #s 322864 & 5.

Note. Doing this will likely require using higher octane fuel.

 

[jimmbo]

Re: Performance parts for 79 135hp?

The part numbers quoted above are from the 1978 and 79 140hp, they were not as tight as the heads on the 1974-76 motors. The 1973 135hp had the highest compression heads. The 1978 and 79 140s had 1 3/8 " carbs. The 1977 140 had the best exhaust tuner

 

[emdsapmgr]

Re: Performance parts for 79 135hp?



This is a picture of a 135 block with the special 140 cutout added to the lower exhaust chest.

 

[Tim Frank]

Re: Performance parts for 79 135hp?

Cheaper to save the prop and install a 150 HP.

 

[jimmbo]

Re: Performance parts for 79 135hp?

Cheaper to save the prop and install a 150 HP.

No savings there, Prop is the wrong hub size.