Using multiple base gaskets??

Ok I have a last production 390cr cylinder. I'd like to use it on a 430cr bottom end.
The problem is the 390=71mm stroke while the 430=74mm stroke. So that's a 3mm stroke increase. Technically it's a 1.5mm increase at the top and 1.5mm increase at the bottom. So installing two base gaskets should work. I might need a thin spacer. What glue would you use to stick the base gaskets together?

The older pre '82 390 cylinder has about 3/4 in size of the transfer ports when compared to the newer post 82 cases. There's room to match the 390 smaller transfer ports to the larger transfer ports in the newer case.

Does anyone polish the inside of the crankcase for easy flow?
I seen a engine builder do this on a husqvarna chainsaws for better smoother flow. Is there any info on doing any porting on the lower cases? I'm thinking of building one animal hairy ride not for the faint hearted.

Just a future thought. I have three big bore cases and two bikes. I have an addiction of going on a binge building engines. Then I restore one bike at a time.
I'm a sick man.

As a rule, polish exhaust ports and leave surfaces where fuel is present as rough as a rotary file or die grinder leaves it. The roughness will aid in getting any liquid fuel atomized again should it fall out of the air stream.

Personally the torque if the cylinder to the crank cases will hold the two gaskets tight enough, i would smear greese between the edges just to ease removal and ensure its sealed as it will squelch out under tightness.
Good job on the collection A*

I admit I have a problem I'm a hoarder when it comes to hobbies. I jump in with both feet with no hesitation. I have one complete 82/430cr all apart. Another 82/430 still gathering parts here and there. I have a 87/500cr bottom end. Plus my 84/250wr. Not bad for 9 months of gathering.

Never rode a cr but the 430's go like hell.

I had most of the late 70's to '86 husqvarna dirt bikes. I really liked the '79 cr390. I think I stayed riding it too long over the others. When I switched from the 250's to the 390 the difference is power was awesome. I wish I never sold my assortment of husqvarna bikes years ago. But I'm back much wiser now.

I understand the affliction. I just bought a trashed 450CR and was ready to buy a 360WR but someone else beat me to it.

My other affliction is the Honda CBX I have four of them that need total restoration. It's really a ballbuster finding and fabricating parts for the CBX so I thought I would take a break and try my hand at restoring a dirt bike, I think I am going to enjoy it. I can lift the engine and set it on the work bench, no valves to adjust and one carburetor to rebuild....lol.

Why not simply put an LC400 sleeve into a 430 430 cylinder and built yourself the AC 400 that never existed. Then you have all the oversizes for the 400 and the 430 to go through before needing another sleeve. Then you do not need to stack anything out.