VAC

[41106]

My engine is tired, and thinking that I would replace engine with bigger one if possible. I searched the archives, but sort of found conflicting info. I don't want to put anything huge in it, and I want it to look original. (might pull at local fair with it) If I locate a 430 or 530 with a 2 bolt starter, will it fit? Or is it only the 148 that will fit? Also, anybody know what hp these 2 engines were rated at? Thank you
 

[VACLee]

The 126 from a 200B or the 148 from a 300/300B are the only ones that will bolt in without modification. They are about 5/16" longer but usually that can be worked out in the sheet metal. The 148B as in the 430 has a different bolt pattern on the flywheel end to clear the larger flywheel and clutch. The 148 was rated at 32, but that appears to be some what conservative from the dyno work we have done. Lee
 

[41106]

Are the 300/300B engines hard to find, or quite common?
 

[VACLee]

Probably depends on location. In my area (central NC) they are pretty hard to find. At that time there were not a lot of dealers in this area. In talking to other people in some areas they seem to be readily available. It also appears they were prone to break cranks. In the salvage yards I visit the mostly complete engines will either have a broke crank or the crank will be gone. Another option you have would be installing a 3 7/16" overbore kit in your engine. That would give you 139 cubic inches. May very well be the least expensive because any engine that you find probably will need to be rebuilt anyway. Lee
 

[41106]

Thank you for your help and knowledge. Now one more question, with a 3 7/16 bore, and minor porting to the stock head, carb adjusting, etc..., would it be possible to hit the low 30's in hp or am I way off? Who's a good source for a kit like that? I guess that's 2 questions hahaha Thanks again.
 

[VACLee]

I think with mild porting and about .125 cut on the head 30 could be reached. The kit is pretty easy to find. About all of the piston/sleeve kits for that engine will be the 3 7/16". They are available on this site. Plain kits are under tractor parts. Combination kits with bearings and or valve train parts are under engine kits.
 

[1031D]

I have 2 with 3 7/16" pistons, G148 camshaft, one size up main nozzle, and a mild port/polish job running low 30's in farm service.
 

[41106]

Is this with the VAC head, or a newer one?
 

[Thad]

Ive got one i build thats around 35hp. The basics of it are 3 7/16 bore .175 shaved off VAC head with some mild porting. I used a cam from a 500B 600B all other cams are the same specs. A 148 cam checks identical to a VACs as did the 159s. The 600s has more intake duration than the others the lift was the same as the others. It pulls 35hp on my dyno at 620 pto rpm. At 540 pto its low 30s and my dyno is a little stingy. But the engine likes to run the higher rpms because of the higher duration in the cam. I changed a few carb parts also. Good luck Thad
 

[1031D]

I have a VAC head with .125" shaved off and the intake ports are opened up a bit.
 

[Augie]

Ours made 33hp at 540pto on M&W dyno with the overbore kit, Pertronix ignition, and lot of head work.