I have a Sherman M4A3E8 and I do the conversion by scratch to the M4A3E2 Jumbo and I need some pics.
Helper are wellcome!

I don't think you can get from here to there...Sherman experts will refine the comments.
First, the M4A3E8 uses HVSS suspension (that's the "E8" part) and the Jumbo uses the older VVSS suspension.
Second, the turrets are different. The M4A3E8 uses the later type turret with long 76mm main gun. The Jumbo uses an uparmored version of the older type turret armed with the 75mm gun.
Third is the hull. The Jumbo has a thickened hull and different transmission cover or "nose".

Kind of like wanting to turn a new VW Beetle into an old VW Beetle or vise versa.

I'll second that info Rob But some of the Jumbo's were updated to the 76mm in the field However an M4A3E8 would look interesting with the Jumbo armor I may do that as a "What If" tank Maybe even add a 17lber

Rob I change the suspension, and the turret I build from scratch...but the hull that´s the problem...

Again, I'm not a Sherman expert. Tamiya does an M4A3E2 "Jumbo" but it has been criticized as inaccurate. It "looks" like a Jumbo to me, although I do recognize the errors. I know Tank Work Shop does a nice conversion set. Scott Dimmick had one listed for sale here in the "Buying/Selling" forum recently for $32 delivered, an excellent price. This complete conversion will turn just about any Sherman into a Jumbo.

Tank Work Shop also sells the hull, turret, gun, nose all separately.

Tamiya uses their standard M4A3 hull with add-on armor for the sides and front. Once you get the uparmored nose, you should be able to add sheet styrene of the appropriate thickness to the front and sides. Either that or look for TWS's upper hull.

I believe I have an ancient resin Jumbo turret that I do not need. You are welcome to it if I can find it.

blast-models is going to release a jumbo version very soon... it will be a complete kit with plenty (using perhaps a bit of plastic from someone else) with plenty of resin. I saw the master in their shop, and it's a beauty. If you check their site, you'll be able to find plenty of close-up pictures.
Well, sorry, that's not going to help you scratchbuild your own jumbo... #:-)

They used the new 47 degree glacis hull, but kept the dry storage. They added 1 1/2 inches of armor to the sides and front of the hull, this would be easy to scratch build if you can convert it to the scale you need, also the front only had the barrel travel lock and lifting hooks. For weld marks these need to stand out, which again would be easy to do, and one more note the added weight to 42 tons all of these were permanently fitted with duck-bills, and as for a 76 most of them if not all stayed with the 75mm M3 gun due to the fact there was no advantage in firing HE through the 76.
My wheat pennies worth......Can not wait to see it done!

www.jagdtiger.de has a couple of pictures of the Jumbo.....these may help a little bit.

H.M. & G.B.
Robert

Thank you guys, this sites really help me.

Rafael

http://users.swing.be/tanks/engins2/76.html
http://www.onwar.com/tanks/usa/profiles/fpm4a3e2.htm
http://afvdb.50megs.com/usa/pics/m4sherman.html

Not a whole lot here, but might be worth a peak.