I am thinking about going a different route than what is normally recommended on this site. I am going to have Performance V Twins mod a pro drive to the 45 Mag....Connecting Rods, Flat top Pistons, Rockers, SS Valves, push rods, cam and truing up the heads. I am not concerned about top end speed, just load carrying...if I am running 27-28 with a normal hunting load on a 1754 I am happy.

For the guys that have experience with this set up, what should I expect? I know the 45 mag has a great reputation for reliability and torque...the two things I am looking for, but I have zero first hand experience with this set up. Thx for the input....

Can't speak for the PD but the 45 motor may not give a lot more speed but you can load her down and not see the decrease in performance w/ a stock motor. Take it easy w/ the heads and don't overdo things and it will stay w/ you. The addition of a single carb will really make it haul.

Thx Man...Any other opinions on the 45 Mag?

He had bad luck with the mikuni on his last rig which is why he's going stock this time.

SP, you always forgettin' the cam man!

I can't get anything by you Clay! ..

I wouldn't say I had a bad experience with the Mikuni, it is a good carb. I picked picked up about 1 MPH with it. It just adds a level of maintenance that I could do with out. I am hoping I will be happy stock..but if not, never say never....Interesting that Al recommends a different Mikuni than the HSR, but he is testing the adapter for a vertical now....

I went back and read a ton of threads about the 45 Mag, and it sounds like a lot of guys are running at 4600 RPM's with this power head. It will be interesting to see how this is going to perform on a CDI motor. My next step if I were to do anything would be to do a light decking of the heads of around .020 thousandths... but we will see.... I am concerned about building up too much compression with the combination of the internals of this design and modded heads...This concern is why the Mikuni is still on the table...

I was not displeased w/ the stock carb at all. I just enjoy the extra kick of the Mikuni. You will be happy either way. CB is right, cam is critical to the performance of this setup & probably the major reason for the load carrying performance.

Don't the BPS 5500 and 7000 motors both use the same pistons with heads decked at .030?

Al is shaving the stock pistons and using .120 over rods right?

Then I think that is still the same recipe BPS is using. Curious why Cody would say not to do the heads.

I have the BPS 45 kit, Mikuni, and IM heads on my 36PD pushing an 1854 PD boat with a side console. My boat has all the extras... extended deck, gun box, livewell, hydroturf, a self made deck on the last 1 1/2 foot foot of the boat where the dog sits, hydro pumps for the tilt and reverse, huge battery, permanent dog ladder, and lots of other extras I'm sure I'm forgetting that add a ton of weight.
I put the mods on in stages. The stock motor would push the boat 24 empty and 21 with a load. The 45 kit and Mikuni would push the boat about 26 loaded and a little over 29 empty. With the IM heads I can cruise around at 31 - 32 with a light load and about 28 loaded down decently.
When I put my hardsided blind, 3 guys with hunting gear, propane heaters, 95 lb dog, vortex with battery, 5 spinners, about 7 dozen weighted keel decoys, and other misc. junk, I can get up to 28 but mostly cruise around at about 25 or less in deep water. I tend to take WAY too much junk out hunting with me and the boat always planes out no matter what I have in it.
I would do all the mods again in a heartbeat. They have been reliable for me and have given me the load carrying ability I was looking for. If you're already getting 27-28 with a hunting load, I'd expect you to get well over 31-32.

Yeah he is shaving the stock pistons. They are not completely flat.

Wolfmann- thx for the info. What RPM's are you running? I am assuming you do not have a CDI...

No CDI, but I don't ever go about 4400 anyway, 4150 to 4300 is my sweet spot with a load. With a light load I'll go up to 4400 but never above that. I don't know if that's the key to reliability or not but I'm not chancing have that much money go up in smoke for a couple hundred RPMs.

I thought that may have been why you said that.

BPS is using shaved stock pistons also, right?

I just spoke to Al....he does not disclose exactly what specs he uses...he "optimizes the compression" for for 92 Octane gas using the recipe below:

He machines the stock Pistons, so they are "basically flat"
Installs a high lift Cam with lifters- his design from a blank, not welded.
Installs a Custom "longer" Con. Rod
Custom push rods
shims the valves
Custom Rockers
Cleans up the Ports or fixes any imperfections in the stock heads, If needed
SS Valves- he just got in the exhaust valves today (new design) installing both intake and exhaust SS valves

I am not disclosing anything he would not tell you if you called. I will say though if he told me the exact specs I would not have posted them, as it was obvious they are his sauce. He recommends breaking in the motor for at least ten hours with the stock carb before adding the Mikuni. That way when you are jetting the Carb, you are jetting a motor that has loosened up.

Sid at Fast Duck Motors did most of the work. It has a Mikuni, IM heads, Rockers and Push Rods from him and the original Cam and exhaust from Gecker. The motor is solid, but I am selling it with my rig....

from 45 mag up, have all the same internals. 5000 is stock heads and single carb. 5500 is Iron Mountain heads and single carb. 6000 is dual carbs, stock heads. 7000 is iron mountain heads and twin carbs.
I am not sure how the rev limiters are throughout the models.

This is their business. I get it, and I respect it. I am sure if I pressed him he would have told me, but frankly it wouldn't make a difference to me. I just need to believe in the philosophy and the capability of the person doing the work. The details of how to are why I am hiring them and not doing it myself...it is not what I do.

The old adage, I just need a watch, not know how to make one.....

I wasn't singling Al out and I understand why he is not giving specs out to the MM crowd. I bet he gives specs out to the kart and tractor guys though. Just saying it's funny, most of us MM folks don't really care where others working on the same engines wouldn't even look at the parts unless they knew everything about them.

Everyone makes a big deal about ideas gettin copied but in reality its part of any buisness. Everyone is chasin the other guy. I bet ford has lots of gm cars torn apart in their engineering dep.

I got this note from Al today....

"I am finishing up the engine today. The ports did need some attention so I went ahead and did our 3 angle job on the seats and installed the intake valves as we discussed."

You have got to love Briggs quality....this a brand new motor....

Thx DB. I will check out the instructions. I am hoping I don't run that high, but I we will see...