slydog

Ok yeah it was funny. The news from Ayr was not so funny tho.  If it's true we are all going to look silly. 

I'll chime in here with my 2c:

Clevos were hampered by the need to squeeze the medium-block V8 shape into what they called "compact" cars in the states, one of the major hurdles was tucking the exhaust manifolds under to clear the shock towers in the falcon/fairlane/mustang engine bay. The only practical way to do this (but still have adequate performance) is to curl the exhaust port downwards sharply to meet the tucked-on manifold ports.

This was fine at the power levels that the road cars came with, but as race horse power kept going up, this port design was becoming more and more of a restriction. The 4V head is actually worse in shape than the 2V, despite having a bigger cross-section.

As the 4V was the only head that anyone bothered to race with, it was why port plates came about. Even then, they were a race-only addition as long-term use would give sealing issues, etc.

The crossflow head is not hampered by such space requirements, so the ports are nice and straight. They can keep velocity up but as Sly mentioned, still flow more than enough for what the engine can handle. The biggest restriction on the pushrod 250 would be available valve size rather than the port, due to the long stroke/small bore arrangement.

This is why the OHC, with its Hemi arrangement, could fit bigger valves and make more power with all else being equal.

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Jason Murphy and couple other started/tried but stopped just like clevo guys did when they found they could use filler instead.
The cost of the work involved for the potential outcome of predicted cfm demand outweighs the benifits.
CFM demand is the first question you should ask before building a engine and I would be extremly suprised if any one with a xflow on here needs more than a stock ported xflow head can give. They can work awesome if ported correctly but as the saying goes,you wont know if you dont try so knock your self out.

Port tongue plates, fitted as part of a gasket.
 
Port filler used to reshape the hole...
 
 
Port plate, heavy machining required to install.
 

Jason Murphy and couple other started/tried but stopped just like clevo guys did when they found they could use filler instead.
The cost of the work involved for the potential outcome of predicted cfm demand outweighs the benifits.
CFM demand is the first question you should ask before building a engine and I would be extremly suprised if any one with a xflow on here needs more than a stock ported xflow head can give. They can work awesome if ported correctly but as the saying goes,you wont know if you dont try so knock your self out.

Starting on the new head next week. Testing has shown him what he wanted to see and plan for. 
Black top dyno showed it made "real hp" even though it lacked epic cfm figures last time so this time will be no different im sure.

Starting on the new head next week. Testing has shown him what he wanted to see and plan for. 
Black top dyno showed it made "real hp" even though it lacked epic cfm figures last time so this time will be no different im sure.

Testing testing testing...low lift mid lift up some more and couple more numbers up top.Room to move still 🤛

Core shift is a concern for sure hence the chopping a couple up and keeping a average not chasing to go as far as possible. That and boost will aid in any HP shortcomings👊🏽

Core shift is a concern for sure hence the chopping a couple up and keeping a average not chasing to go as far as possible. That and boost will aid in any HP shortcomings👊🏽

yeah that is smart thinking,
i'm a big fan of the CNC porting with this in mind(wonder how much they allow for core shift?, the black clevo heads were better for porting for this reason)
 

See where water is and how much material is where and to profile the port. He has done lots of Chevy Ford Holden and LS stuff but only 2 xflows. This been the 2nd. My NAT ASP head the first.
I know local shop just sent a Iron Windsor head over to Kuuntz in the US so they can  do the same then CNC duplicate for future use. Smart thinking imo.

See where water is and how much material is where and to profile the port. He has done lots of Chevy Ford Holden and LS stuff but only 2 xflows. This been the 2nd. My NAT ASP head the first.
I know local shop just sent a Iron Windsor head over to Kuuntz in the US so they can  do the same then CNC duplicate for future use. Smart thinking imo.

were scrap heads sacrificed for to see where the water lives? or is this a result of keeping port size and having great skill in the valve/pocket area

Test port for the boosted head has gone over the old NAT ASP head total figure by 500lift already. Its 22cfm better by 200th aswell.
Wonder if he had been playing with xflows for 20 years how they would flow,seeing this is his 2nd ever.

Test port for the boosted head has gone over the old NAT ASP head total figure by 500lift already. Its 22cfm better by 200th aswell.
Wonder if he had been playing with xflows for 20 years how they would flow,seeing this is his 2nd ever.

Test port for the boosted head has gone over the old NAT ASP head total figure by 500lift already. Its 22cfm better by 200th aswell.
Wonder if he had been playing with xflows for 20 years how they would flow,seeing this is his 2nd ever.

They need to keep the valve under control hence needing duals or tripples with dampers. 
Modern spring material helps but spring pressure is needed regardless. 
 

This ^^^ old school look modern running
 

If you want my opinion (Hahah, Good one.) wihout reading the whole thread.

If you want EFI.
Fucking put it on. 
There is little to nil excuse for using throttle body injection of aftermarket "Bolt on" self learning systems when proper EFi installations can be adapted and used so easily with much better results.

If you want to keep a "carb" manifold and look. Just leave the fkn carby on it..

His name is Chris,nice bloke and did Tony Spaznoski's combos. Yes he swears exactly like that in person too.
The hp gain for them is easy to explain. The exhaust and inlet are on the same side.So if you have a tube pulling air from the grille getting air forced in by a fan thats cooler than under bonnet temps it will make more hp.
I would suggest using the EF El intake as it works and fits better. Quintin aka crazy did it years ago and alot better than Clints effort.
Having a solid roller webers and 13:1 comp idle @ 950rpm in gear and handle traffic like anything else I often hold back from commenting as I know how different real life is to internet life. Quintin drove the car like 300-400kms and we even loaned a fellow LS powered racer some fuel as our economy was better than theres was. I know right...better than a EFI LS.So again the Webers (which were standard fittment on BMW Ferrari Mazaratti Lambos the list is endlist) came out beter than all thought in real life. 
Look up Bud Moore intakes. You will see how he used twin 1050 dominators on flat tappet 289-302 Windsors and 302 chevs that worked so well they got banned.
So will you actually fit tripples to anything ??? Ill say no but you sure would have a hell of a experiance if you did.The noise is so addictive,the wow factor is huge and your street cred would surprise you. The power... well smoking 275x60's to limiter in top gear from a dig no brakes for as long as your game makes it all worth the effort.

Im actually keeping em and the NA cyl head now. Im build a 2nd forged bottom end like the current one and just have 2 engine combos to use as I feel.

Nope...the manifold uses a thick 20mm or so spacer and thick gaskets and to tune em right you need to be able to fit a syncronizer to the carb bell to set em up.
Needed room for that. All this bull shit about space is just that bull shit. Ive seen cars on dynos where you close the bonnet with 5mm above the carb make exactly same hp bonnet open or closed.
As for carbs to use no carb beats the webbers. The fab work involved in the 3 Holleys is too much and they require a serious engine to work. Webers work on stock or race type deals.
Tuning em is sooooooo easy and parts easy to get. 
 
My vote Webbers for lyf
 
PS the air box is no faster than just open carb trumpets too. Ive done it waaaaaay too many times to be wrong. On the street it may be better  but my deal no way.

Im actually keeping em and the NA cyl head now. Im build a 2nd forged bottom end like the current one and just have 2 engine combos to use as I feel.

Nope...the manifold uses a thick 20mm or so spacer and thick gaskets and to tune em right you need to be able to fit a syncronizer to the carb bell to set em up.
Needed room for that. All this bull shit about space is just that bull shit. Ive seen cars on dynos where you close the bonnet with 5mm above the carb make exactly same hp bonnet open or closed.
As for carbs to use no carb beats the webbers. The fab work involved in the 3 Holleys is too much and they require a serious engine to work. Webers work on stock or race type deals.
Tuning em is sooooooo easy and parts easy to get. 
 
My vote Webbers for lyf
 
PS the air box is no faster than just open carb trumpets too. Ive done it waaaaaay too many times to be wrong. On the street it may be better  but my deal no way.