Top speed for a vintage 272 LS?
 

I am only showing 47mph gps I thought I saw some others getting closer to 60mph. I have the twin small blocks. with no power upgrades other than edlebrock carbs. I have 21p cleavers I think they are cleavers they are really old. it runs really strong oh and this was with four on board and maybe quarter of a tank of fuel.
I am still learning the trim game too. They were trimmed all the way up and my tabs were up too. so if you all want to share trim secrets let me know.
before this boat all I have owned is squirt boats.

Re: Top speed for a vintage 272 LS?
 

My 242 ran 62-65 with twin Sbc's.

Re: Top speed for a vintage 272 LS?
 

You should be doing better than 47 mph. We need more info. What rpms are you turning at full tilt? Trimming all the way up is often not going to produce top speeds (cavitation). Is your hull dirty, moored in water? After these basic questions, then we need to know how you know the engines "run really strong". No offense meant here but, 47 mph doesn't sound like strong engines to me. Rebuilt lately? How many hours? Post some pics of the old bird for us. :cool:

Re: Top speed for a vintage 272 LS?
 

hey third let me try and answer all the questions, its a trailer queen the hull is clean. I can't give you any concrete info about the engines other than they run smooth no missing and have a very snappy response, fire right up. They just don't skip a beat. that speed was at 5000 rpm's in fresh/salt water river. tonight i got em up to 5200 but didn't have my gps. What is the powerband in these old sbc's? what rpm's is the max spec? not sure when the last rebuild was or if they have ever been gone through, It has 540 hours on it.

I am rookie at the art of trim also. I trimmed until it stopped speeding up then back them off a tad, plus only one trim gage is acurate while under way. it works great at the dock but as soo as I get gong it just pegs to the top. my drives are kinda beat up the have some chips and gouges on the front and on the bottom. not anything major but not smooth. I may be doing something all wrong? who knows thats why I am here though.

Re: Top speed for a vintage 272 LS?
 

Our '83 272 with twin 260 Mercs ran 62 when new radar confirmed.

Re: Top speed for a vintage 272 LS?
 

you should get rid of those old cleavers and try some 21 Mirages........peak power is 46 to 4800..............doug

Re: Top speed for a vintage 272 LS?
 

is that what these are? not exactly sure all thats stamped on them ys a # starting with 48 then 21p

Re: Top speed for a vintage 272 LS?
 

That's the way to do it, you're trimming as efficiently as possible. Gotta agree with Pull my Trigger, those cleavers are probably holding you back some. Sounds like the engines are trurning up a few too many RPMS, maybe you can handle some more prop, like 22-23 inchers.

In any event, that's a really nice looking boat. Congrats. :cool:

Re: Top speed for a vintage 272 LS?
 

thanks third, I am going to try mirage 21's and 23's see what happens.

Re: Top speed for a vintage 272 LS?
 

Like Cuda, my 242 ran out around 65 mph with twin small blocks and thru transom exhaust. I was running 23 inch "cleavers". This was back in 94'.