Will a 323 sohc B-6 head directly bolt onto a Festiva B-3 block?

[Doug Brown]

Will a Mazda 323 sohc B-6 head directly bolt onto a Festiva B-3 block? If not, which sohc B-6 head will directly bolt on?

Do all sohc B-6 heads have the same size inlet and exhaust valves?

I know there maybe an interference problem with the valves/cylinder bore walls/block -- that's why I want to get a B-6 head to work around the problem.

Does anyone have a complete sohc B-5 head for sale???

Thanks

[firebush357]

Good Afternoon Doug,

I have looked into this a little as well and haven't really found a good solution. The B3 engine has a 71mm piston where all of the B5 and B6 engines have a 78mm piston so you would probably run into problems with the valves hitting the block unless you do some major boring of the B3 Block. There is one guy that has supposedly used a piston from another engine that was machined to custom fit a bored out Fesitva block at like 75mm I think but I don't remember the details.

As far as the valves they are all different as far as I can tell. There has been one person that I know of that cut in larger valves on a ported b3 head. I am not sure what valves he used but I found some of the B6 valves that are close enough in length that they would work in my mind if you wanted to cut new seats. If you are interested I can do the research again and try to send you some details.

[Doug Brown]

My plan for getting the valves NOT to hit anything is to have the camshaft re-ground with less lift, but longer duration to make up for the less HP from the shorter duration.

I know the combustion chamber won't be a perfect fit to the bore, but on the 4.2 Jaguar E-types I use to race the chambers were all over the place in relation to the bore - and it didn't make any difference in performance or power output.

What I really need to know is if the B-6 head will just bolt onto the B-3 block. If so, that's the trickiest part of the whole deal. If it will, then I can do measurements for the new reduced camshaft lift.

I think I need to get rid of the hydraulic lifters and just go with the old fashion adjustable lifters.

[firebush357]

I will ask around the Facebook group and see what they know.

SkeetersKeeper just said that they will bolt up but some of the Water and or Oil Passages do not like up. Not sure about the 16V B6-ME

[Herbalist]

I can tell you that a b3 will bolt perfectly to a b5 or b6 block but not sure on the other way around. BTW why do you want to do this?

[Doug Brown]

To get the big valves and the slightly larger ports.