[gongchuan]

And just so you can know what were talking about here........

1986 American Skier "Barefoot Skier" Advance

Here is a shot of the ole girl.

I wouldnt be touching the engine if it were not for a rod cap giving way in the first place, but the entire boat has been gone through (stringers, floor, transom, paint, all hardware powdercoated, decals being made as we speak, so on and so on) and I dont want to play with the old school 2 piece rear man and flat cam anymore. Give me a 1 piece rear and roller block all brand new baby!

[oldbogie]

Originally Posted by gongchuan

Absolutely I was looking at the 4 bolt. I just didn't understand why they made it a point to specify not using a Carb. Ill be turning 3500 rpm most of the time and 4500 to 4700 when I'm playing around or barefoot skiing.

What are your thoughts on a Carb in this situation? I'm now running a 650 cfm edelbrock marine.is that going to be to much? Not enough?

thanks again for the reply. I really appreciate the information.

Given your RPMs a 650 on a 350 is just about dead on.

I don't understand the carb use restriction unless this is a legal thing concerning SMOG engines in road vehicles to reduce their liability to law suit when these things get caught at emissions inspections. As I said; there are thousands of these, either as crate motors or equivalent builds from the parts, out there with carbs on top of them.

As is typical of L31 Vortec heads when your valve lift starts getting around .45 inch you need to pay attention to the guide to retainer clearance and modify the top of the guides as necessary to maintain at least .050 inch of freedom with the stem seals in place.

Bogie

[googala7]

Like I said , .... sounds like you are,"ON the Beam" with what U need. JUST let me remind you something you already know,... GAS IS s#@&**%!!!. I am sure you already have your timing back to 32 -34 total. With this stuff they are selling today it is so easy to,"HAMMER" an engine [even at 9 to 1]. There are really high cylinder pressures involved in getting over the mountain [getting your boat on plane]. Keep it in mind , and you will be OK [WHEN YOU MOVE THE TIMING BACK YOU HAVE LESS TORQUE TOO].

[gongchuan]

Originally Posted by oldbogie

Given your RPMs a 650 on a 350 is just about dead on.

I don't understand the carb use restriction unless this is a legal thing concerning SMOG engines in road vehicles to reduce their liability to law suit when these things get caught at emissions inspections. As I said; there are thousands of these, either as crate motors or equivalent builds from the parts, out there with carbs on top of them.

As is typical of L31 Vortec heads when your valve lift starts getting around .45 inch you need to pay attention to the guide to retainer clearance and modify the top of the guides as necessary to maintain at least .050 inch of freedom with the stem seals in place.

Bogie

Im talking with Comp right now about my lift situation. I will be throwing a set of beehives and retainers on since that is an upgrade I can do without pulling the heads. Not that I mind pulling heads but since its a crate I want to leave it alone if possible.

From what I am being told this should take me from about a .450 to a .550 (safe) lift. I would imagine I can get a fairly nice cam that will work in this range.

[googala7]

Plz remember my quote:" Bigger is not always better" [changing gears , and idling along to take up the slack in the ski rope]. With the mildest cam you should still be putting out almost a HP. per cubic inch [even with 9 to 1]. Tuning is everything. I could recommend a tuning kit from Carter [same as Edelbrock carb]. IT was available years ago. IT was called "Track Pak" ,or something like that. The kit consisted of ,... 4 sets of metering rods, and 4 sets of jets. You could "Mix and Match" until you got your set-up just right. They weren't cheap,... I think it was about 75$ of 1980s money. I think some of those kits are still around, or maybe Edelbrock sells something like it [since they bought the rights to produce Carter carbs].

[gongchuan]

I already have one of those kits from Edelbrock...... used it to tune in the carb to the old engine. Just going to have to make changes when I get it on the new engine. Already ahead of you on that one thanks!

[gongchuan]

You guys have given me some really great advice and I appreciate it! I'm just going to continue my questioning here as it seems you guys are very knowledgeable.

Flex plate.... what do I do for a flex plate or flywheel in this situation? I'm running a velvet drive transmission and am under the impression I need some weight to make everything work properly. Like a flywheel instead of a flexplate.

Any idea as to what I'm going to need to do here? Can I use my old flywheel somehow? If so how do I balance it properly?

[googala7]

This starting to get a little tricky since new one piece seal engines are externally balanced, and older 2 piece engines are internally balanced. I think I would lean toward using the original flywheel , but , you will have to look into the balancing problem. Check me out,.... I am pretty sure I am correct about this....

[oldbogie]

Originally Posted by googala7

This starting to get a little tricky since new one piece seal engines are externally balanced, and older 2 piece engines are internally balanced. I think I would lean toward using the original flywheel , but , you will have to look into the balancing problem. Check me out,.... I am pretty sure I am correct about this....

You need to change the flywheel or flexplate to the 1 piece seal config as the bolt circle to the crank is smaller at 3 inches than the two piece. The offset weight in minuscule all it's doing is off setting a tiny glob on the end of the two piece seal crank that is removed with the totally round end of the one piece crank. In the strictest terms, the old one piece crank wasn't internally balanced as it had a small piece outside the block, but it didn't require additional weight in the damper or fly/flex as the 400 crank does.

Frankly, I was hesitant to recommend this up front, but I think that building an engine from pieces is the best way, at least technically, to go. Most crate motors either run you into the problem you're having where the one piece seal engines get more efficient heads (i.e. Vortec or Swirl Port) while the two piece seal engines tend to get the old inefficient SMOG heads. Where if you roll your own you put it together off a Chinese menu picking a two piece rear seal block and crank, some nice custom rods, and choose the pistons and heads to kick up the combustion efficiency like flat top or D dish pistons probably in forged for a boat, some vortec style heads but maybe aftermarket like RHS or ATR to name a couple, GMPP also makes a much more robust version of the L31 Vortec that is better suited to performance and heavy duty applications these being part numbers (not casting number)25534421 and 25534431 both use the same 2.02x1.55 valves with the 421 having 180cc ports and the 431 having 210cc ports and considerably thicker castings and already machined guides to take high lift cams.

This is a much better way to go than crate engines but it will cost more. This is the way I go, I don't use crate motors unless the customer is adamant about it or the track rules require it.

Bogie

[googala7]

THX Bogie [for the info]! I thought from previous posts he was commited to a crate engine. I don't interchange parts much on the new motors. I recommend the old blocks, coz so many parts are available, ... soooo cheap.... and I like the older blocks [Smokey Yunick ran an 010 block at INDY { finished 13th}]. ALL those new heads available sure are "TRICK" [it is hard for me to keep track of them all. But,... in this instance, you need the velocity at low rpm to get it "over the mountain"[up on plane]. The smaller port heads will work just fine... There is probably an advantage to running the "Vortec" type head,coz you don't have to worry about pre-ignition near as much,but, I don't think it is cost effective in this application.