My new stock stroke 400 build

[qkcuda]

Also accumulating some needed transmission parts, a stock converter weighted for a 400 for conversion to a 2500 stall, and a tailshaft housing with the ears for the floor shifter.

 

[qkcuda]

We were on vacation for two weeks before Christmas. I finally got to spend a day in the garage. I decided to start with port matching the heads. I traced the intake gasket and the scribed the edges. The intake ports on my 516 heads were nice and clean. These 346's were not. I squared them off and removed a lot of casting lines so there was a smooth transition into the port. I only got one done. My little compressor kept kicking out. I may have to upgrade my compressor or go to an electric die grinder instead.

 

[qkcuda]

I also pulled the frost plugs from the block and got a pleasant surprise. The water jackets were amazingly clean, not like my last 400. Looks like it was never run without antifreeze.

 

[qkcuda]

I delivered the block crank and rods to my machinist this morning. The good news is that he agrees the crank should only need a polish, and that there is hardly any ridge in the cylinders, so it should easily clean up at .020 over. We might end up going .030 over depending on piston and ring availability. We also agreed that he would cut the deck surface .025 which will bring the KB 240 pistons close to 0 deck. This will make up for the additional thickness of the composition head gaskets, and give me more options regarding heads in the future. For now I will be running the original 346 heads I am working on, which will put compression in the 8.5-9:1 range so I can run regular gas.

The bad news? I appear to have smoked my light duty oil less air compressor on the weekend, so the search is on for a good used replacement.

 

[PRHeads]

The first attempt at “porting” I did(which is a bit of a stretch of the term) was done using a small die grinder and an old sears 1hp compressor.
It would only sort of maintain about 25-30psi……so it was slow going.
Plus, I was using “stones”.

Spent a bunch of time doing those heads…….and may have even improved the flow a bit.

I can’t imagine an oil-less home shop type compressor………and porting…….are a good match.

 

[qkcuda]

I didn't really think about it but the last two sets of heads I worked on were when I still had my old Sears compressor (maybe 2 HP) running on 220 volts. I do use a carbide bit, and yes it is slow going. This compressor was not up to it, and I am looking for another heavier duty compressor now. This will likely be the last set of heads I clean up, and I have lots of time, so I will give the new compressor, and myself, regular breaks.

 

[qkcuda]

I found a pretty good deal on a used compressor today, 60 gallon, 7 HP, 240 volt. I should be back in business soon.

 

[Orig69]

Be careful with the short side radius you can use an original cylinder head as a guide as to what it should look like.

 

[qkcuda]

Be careful with the short side radius you can use an original cylinder head as a guide as to what it should look like.

My theory is just to round off the sharp edge created by the plunge cut, but I would appreciate any suggestions or pictures. I will probably finish the port matching I started first.

 

[PRHeads]

My theory is just to round off the sharp edge created by the plunge cut

I like to put as generous of a radius as possible on the SSR, but at the same time making sure you have “completed the turn” by the point where the new SSR radius meets the bottom angle of the VJ.

Some heads just have a little more height there to work with, and on the really low ones……you can only do so much.

 

[Orig69]

My theory is just to round off the sharp edge created by the plunge cut, but I would appreciate any suggestions or pictures. I will probably finish the port matching I started first

I guess you don't have another cylinder head to look at.
I agree with PRHeads in post number 30

 

[qkcuda]

I just remembered that I have some saved pictures on my work computer of my Edelbrock heads from my last build. I'll look them up.

 

[HawkRod]

I would have posted pictures of your (now my) Edelbrock heads, but I realize I don't have any pictures of the ports.

Nice build and I'm following along!

 

[PRHeads]

My comment about the SSR was based on the assumption the OP was working on heads with the 346/902/452 style intake port.
These have a pretty flat shaped floor where it transitions from the floor into the bowl.
It’s really nothing like an Ede head, so I don’t know how much help you’ll get by looking at pics of those.
They’re quite a bit different than 906/915 heads as well.

From a home porting standpoint, the 346/902/452 style intake port is much easier to do, and the SSR is more forgiving(than the 906/915) if the shape isn’t exactly correct.
The pinch is a little narrower as well, and I’ve found spending a little time there is worth a few cfm(if you’ve already done the bowls and SSR).

Properly executed basic bowl/SSR/pinch work to the 346/902/452 intake port will easily get them to 250+cfm.
They’re low/mid-220’s ootb on my bench.

 

[qkcuda]

Thanks for the input PRH. Yes they are 346 heads. Before the Edelbrock heads I did a set of 452's, basic port match and bowl blend, but I added 2.14/1.81 stainless valves. They flowed 250 CFM at .450 lift on my buddy's bench, somewhere I have the sheet. As I recall the low lift flow matched the Edelbrock up to about .400 lift at which point the Edelbrocks kept rising and the 452's laid over. My new cam is only 450 lift, so if I can approximate the last set I will be fine.

 

[qkcuda]

Here is the new compressor versus the old one. I have to get a new belt and change the oil, but I should be good for next weekend.

 

[RemCharger]

Here is the new compressor versus the old one. I have to get a new belt and change the oil, but I should be good for next weekend.

View attachment 1583448

I've got the exact same one. Had to replace the head valves once and I suspect it could use rings, but still working 20yrs later

 

[qkcuda]

How do you replace the belt, loosen the compressor mounts?

 

[blue69runner]

Will be flowing your build. Have fun. Blue.

 

[HawkRod]

How do you replace the belt, loosen the compressor mounts?

I replaced the belt on my father-in-law's unit. On his, you loosened the motor itself.