I’m doing a set right now taking your pointer I’m not going over board just cleaning the casting flaws one question what to fill the heat riser hole in the exhaust valve
@@roberthirshfield3571 hey mate. I have never attempted to block off the crossover. Seen a few folks doing it with molten metal and all sorts of stuff. I’ve thought about stuffing it with steel wool and then applying a high heat steal epoxy. Smoothing it and blending it with the bowl after it sets. But you wouldn’t want it to fail, or it’s goodbye to that cylinder. Not sure if it’s worth the effort.
@@roberthirshfield3571 make sure you blend the bottom of the valve seat cut into the bowls on both bowls. Get rid of any ridges into the throat, but don’t mess with the throat size. The whole idea of this clean up and removing obstructions is to help with velocity.
What are great thing ! Did Craig mention what the hp gain would be around? Cheers Pete. PS this could be gidyup my f100 needs , the poor old girl only has a 302 🫠
Yes! He gave me a great example of a back to back dyno tests they did before and after this mod. I'll cut and paste the conversation for you. I spent an hour today, shooting a video of me undertaking Craig's mod on my first combustion chamber. Video is uploading as I type this and will be published on my channel tonight. Here is an excerpt from my conversation with Craig about this mod with an example of what you've asked about. Craig - "I'll also highlight the areas on an actual head for you. Its a very simple mod and yes it can be done better, but bang for buck, for a home port job with no flow bench, it gets gains and detonation resistance. One particular car I did for example was an XY. It had a 351 stock bottom end and stock 302 heads, so compression was up there. A 2800 stally, stock factory iron 4 barrel intake, square-bore adaptor, 750 vac Holley, tri y 1-3/4 pipes and a 2.5" single exhaust. He was beginning to lose a cam lobe. I did a cam swap, (old cam was a Speed-pro CS173R). I fitted a crow cam 21649 and we dyno'd it. It made 265rwhp. It did suffer from detonation and I couldn't get a good timing curve into it. I talked him into removing the heads to do the chambers, as it also wept coolant at the front coolant passages. The heads were bone stock apart from valve springs and retainers. I did the quick chamber mods and a real quick bowl blend. The pistons were of course 20 odd thou down the bore, so quench was not optimal! Back on the dyno it made 282rwhp and took a good timing curve. Not big horse power, but ok from an essentially stock 351 with a mild cam. For a long time now I do the chamfers on any closed chamber head engine, even if I don't do any unshrouding at bore walls or any other porting at all".
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Great stuff. And there’s also back and front cutting intake valves to increase flow. But not exhaust valves , coz direction of flow is the other way 🍻
The intake valves in these heads I purchased have the back cut.
I’m doing a set right now taking your pointer I’m not going over board just cleaning the casting flaws one question what to fill the heat riser hole in the exhaust valve
@@roberthirshfield3571 hey mate. I have never attempted to block off the crossover. Seen a few folks doing it with molten metal and all sorts of stuff. I’ve thought about stuffing it with steel wool and then applying a high heat steal epoxy.
Smoothing it and blending it with the bowl after it sets. But you wouldn’t want it to fail, or it’s goodbye to that cylinder. Not sure if it’s worth the effort.
I’m trying cargo thermosteel I filled the hole it’s hardened up reall strong so far
Keep us posted on that method. I’d be real interested how it works out.
@@roberthirshfield3571 make sure you blend the bottom of the valve seat cut into the bowls on both bowls. Get rid of any ridges into the throat, but don’t mess with the throat size.
The whole idea of this clean up and removing obstructions is to help with velocity.
@@Doctoradhd1 thank you that’s what I’ve done
I can tell you friend no's what he talking about because those chamber mods will make more power than any other mods
Preach it brother!
What are great thing ! Did Craig mention what the hp gain would be around? Cheers Pete. PS this could be gidyup my f100 needs , the poor old girl only has a 302 🫠
Yes! He gave me a great example of a back to back dyno tests they did before and after this mod. I'll cut and paste the conversation for you.
I spent an hour today, shooting a video of me undertaking Craig's mod on my first combustion chamber. Video is uploading as I type this and will be published on my channel tonight.
Here is an excerpt from my conversation with Craig about this mod with an example of what you've asked about.
Craig - "I'll also highlight the areas on an actual head for you. Its a very simple mod and yes it can be done better, but bang for buck, for a home port job with no flow bench, it gets gains and detonation resistance.
One particular car I did for example was an XY. It had a 351 stock bottom end and stock 302 heads, so compression was up there. A 2800 stally, stock factory iron 4 barrel intake, square-bore adaptor, 750 vac Holley, tri y 1-3/4 pipes and a 2.5" single exhaust.
He was beginning to lose a cam lobe. I did a cam swap, (old cam was a Speed-pro CS173R).
I fitted a crow cam 21649 and we dyno'd it. It made 265rwhp. It did suffer from detonation and I couldn't get a good timing curve into it.
I talked him into removing the heads to do the chambers, as it also wept coolant at the front coolant passages. The heads were bone stock apart from valve springs and retainers. I did the quick chamber mods and a real quick bowl blend.
The pistons were of course 20 odd thou down the bore, so quench was not optimal! Back on the dyno it made 282rwhp and took a good timing curve. Not big horse power, but ok from an essentially stock 351 with a mild cam.
For a long time now I do the chamfers on any closed chamber head engine, even if I don't do any unshrouding at bore walls or any other porting at all".
What a waste of time.
Bit of a blanket statement. I’d say it all depends.
@@Doctoradhd1 2V Cleveland heads are junk. Not worth investing any money in them. On top of that they're low performance heads.