I just did a compression test and my #5 cylinder is dead it read 35 lbs while the rest were good at 185-190 lbs. I am going to tear it down at the end of the season for a rebuild so here are my questions.

1) What is the cheaper option to pull it out and have it rebuilt at a local shop or to just buy a long block ready to go and have it shipped to me.

2) Are there any shops that have the 6.2's rebuilt that someone can recommend?

3) Anyone know of any extras I can have put on like roller rockers, a good set of heads that will work with my MPI?

I posted a while back about possibly going to a BBC but with the exhaust issue and the MPI I just don't want to get into that with this boat.

Check the tread on the 6.2s. There was some good info. I asked if there was some easy horsepower to be had and I got a lot of good feedback. I'll see if I can sum it up: Stock heads, cam, and intake are a pretty good "coordinated" package. The stock heads will not allow additional lift w/o modifying the valve guides. Not enough wiggle room to even add higher ratio rockers. I looked into what it would take to come up with a higher performing package:RHS heads $350 each. Crane cam $426 Edelbrock intake $418 (pro engine builders told me the stock intake was a bottle neck). CMI headers $2500. This package would take you to the 420-450 h.p. range. Other recommendations from the fine members on this forum were H-beam rods and forged pistons for the shortblock. Adding to the expense is reprogramming the computer and possible larger throttle body. I am NO expert at engine building. I just started collecting info. Send me an email and I will forward you all the details I have. This would be a great time for you to make some changes during your rebuild. CMI has back-to-back dyno tests of the engine without and with headers. They show a good 40 h.p.

My motors are fresh and there are two of them so any changes for me will be a long way off. To sum up my rather long summary there was no single inexpensive item that I could find to improve the performance of the 6.2 mpi.

I didn't think about this I am going to tear down the heads and check the valve clearances and make sure I didn't bend a lifter. I know for a fact I got some water in that cylinder. Anything else I can do to diagnose this loss of compression I jumped the gun thinking it was the piston rings and it would have to be rebuilt guess I should clear my head before I go making posts

Where was the 6.2 thread posted wes ?

So in theory just adding the Intake and headers would be a fairly easy upgrade promising good results. Would I still need to get the computer reprogrammed with these mods? if so who can do that I have yet to come accross a tuner mentioning the 2001 6.2 motor mine does not have the PCM555.

so you may have bent a lifter eh? i would take it to your local mechanic and have it checked out,,you may just have a burnt a push rod or have a flat lobe on the valve..

6.2 Posts were on page 10 when I looked this afternoon. Many of the engine builders on this forum chipped in. I am not sure if just changing the intake and adding headers is the proper package/combo. As I said before I am just collecting info. I was leaning towards trying heads and a slightly bigger cam, a Crane with specs of:#109671: 509/528 lift, 216/224 duration, valve spring pressure needed 125/342, rpm range 1600-5800 (3-bolt). Stock cam is: 452/.465 lift, 214/220 @.050 duration (Same as CRANE 2032)Rpm range 2000-5500.

One of the pro builders suggested that my cam choice was a little too mild (he is probably correct). I chose the cam based on very little increase in duration (so no worries about water reversion) but a fair increase in lift. My thought was since I was not really going to increase the r.p.m. range I would be ok with stock intake and exhaust. The heads "could" yield up to 30 h.p. and the cam "maybe" another 10? I know from past experience that is it the combination that counts. Even if you did your own work the parts along would run $1200 - 1400 for this combination / experiment. I was hoping to find someone on this forum that had tried a particular combination but it seems like most are playing with big blocks. No substitute for cubic inches!

Get with Bob Llyod @ Full Throttle Marine he's played wth these,
Did my rebuild last year on my 6.2 we added a Whipple but he's done some without, heads, cam, and intake change along with the ECM reflash is what you will need, he has a good combo. Steve

Osur866,

Did you run with a stock 6.2 before you added the Whipple? If so just curious as to top speed increase, other changes made in addition to the Whipple, and prop change.