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Guy has a bench that draws into a clear chamber so you can inject 'smoke' and see how your intake combo works. (Something developed by Tom Hoover - father of the Hemi (some may recall him) - he lives a mile or so away and is friends with the shop owner...)
anyways. G2 *AND* G3 intake/head combos suck for making top end power. (sorry, I know its heresey - but read on as to why)
the problem in a nutshell is the air does not get 'turned around'
Consider if you will the splayed valve combustion chamber - something with no changes (other than volume) G2-G3. incoming air is essentially straight and when it dumps in the intake port (which is in itself a nice hyper straight shot) the ridge on the plug side shrouds the valve, builds a high pressure zone and forces the air to 'corkscrew' into the cylinder. This is good, but the air has almost no movement getting to the intake port.
Some might remember an intake developed in the late 60's by offenhauser called the '360' degree intake - it caused the air in the intake to swirl before it hit the intake port runner of the head - raising flow. To visualize - consider a funnel - if you pour water in the funnel, it drains faster if you pour at an angle that lets it corkscrew in vs just overloading it.
At any rate these intake designs have been copied for the v8 land ad nauseum and of course got copied onto chevy and buick 90* V6s using carbs and TBI. For EFI, the L98 TPI was GMs first stab, ford had one for the Cobra R, dodge came up with one for the magnum. No such animal exists for the 660 motors, the G3 intakes, although improved and symmetrical vs G2, are about as tuned port as my butt. (and that upper plenum still sucks - GM would do well to steal the design off the Buick C, N and L code motors)
And as a funsie, we tried a 4bbl edelbrock mani for the G1 and a holly 390 4bbl[1] with the throttles tied wide open - and it does what is required (which leads one to the logical conclusion that the guys in midget who build intakes and use carbs on g1,2,3 engines are on to something - they regularly circle with 300hp.
We conducted these tests with valves installed (to do otherwise would be meaningless) we ran at .100, .200, .300, .400 and .500 lifts[2][3] (which is considered max 660 lift in most cases). On stock heads/intakes (no porting was done, they came right off motors from the bin) by .400 lift the combos were running out of steam at 28", they shined .200-.400 and we didnt conduct the test with more granularity - which confirms what I have already seen on paper - a flat ass torque curve - of course the exh performed far worse but consider, it was not heated.
At any rate, stay tuned. Due to a previous 'discussion' on another board I am undertaking a race car project - two actually. My goal is to build a TGP and a T code as high as I can get em, the TGP of course a W body and the T code in a J or N body. I was trying to get base flow numbers before I cracked open the grinder case. In all cases I am trying to keep the EFI. Having Tom aware of this will be a boon, he did a lot of the pioneering work for AFR and should be able to guide me -these race cars will not be pollution legal or most likely streetable - with a 7000rpm redline using milled 'pink' v8 rods and the proper comp cam, it wont idle, run brakes, AC etc
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Notes:
1: the 390 sounds tiny, but for a 3L engine, its more than proper, in some classes, 390cfm is the max carb allowed as is 9.5:1 comp ratio and these guys are north of 700hp with basically 350 cube motors. a 390 will be more than adequate for a carb setup
2: the guy has a tool that screws onto the stud and you adjust a wheel that pushes against the opposite side of the head and opens the valve. You just measure how much you depressed it.
3: at .500 the heads have some serious coil bind[4]....it cant be done, you need to machine the heads to have a pocket to take roughly a 1.38ish spring - but u should get over .550 lift if you do such, there appears to be room.
4: we removed the stock valve spring and installed a spring from a ford AOD tranny 4th gear servo lol. Neccessity is the mother of invention.
anyways. G2 *AND* G3 intake/head combos suck for making top end power. (sorry, I know its heresey - but read on as to why)
the problem in a nutshell is the air does not get 'turned around'
Consider if you will the splayed valve combustion chamber - something with no changes (other than volume) G2-G3. incoming air is essentially straight and when it dumps in the intake port (which is in itself a nice hyper straight shot) the ridge on the plug side shrouds the valve, builds a high pressure zone and forces the air to 'corkscrew' into the cylinder. This is good, but the air has almost no movement getting to the intake port.
Some might remember an intake developed in the late 60's by offenhauser called the '360' degree intake - it caused the air in the intake to swirl before it hit the intake port runner of the head - raising flow. To visualize - consider a funnel - if you pour water in the funnel, it drains faster if you pour at an angle that lets it corkscrew in vs just overloading it.
At any rate these intake designs have been copied for the v8 land ad nauseum and of course got copied onto chevy and buick 90* V6s using carbs and TBI. For EFI, the L98 TPI was GMs first stab, ford had one for the Cobra R, dodge came up with one for the magnum. No such animal exists for the 660 motors, the G3 intakes, although improved and symmetrical vs G2, are about as tuned port as my butt. (and that upper plenum still sucks - GM would do well to steal the design off the Buick C, N and L code motors)
And as a funsie, we tried a 4bbl edelbrock mani for the G1 and a holly 390 4bbl[1] with the throttles tied wide open - and it does what is required (which leads one to the logical conclusion that the guys in midget who build intakes and use carbs on g1,2,3 engines are on to something - they regularly circle with 300hp.
We conducted these tests with valves installed (to do otherwise would be meaningless) we ran at .100, .200, .300, .400 and .500 lifts[2][3] (which is considered max 660 lift in most cases). On stock heads/intakes (no porting was done, they came right off motors from the bin) by .400 lift the combos were running out of steam at 28", they shined .200-.400 and we didnt conduct the test with more granularity - which confirms what I have already seen on paper - a flat ass torque curve - of course the exh performed far worse but consider, it was not heated.
At any rate, stay tuned. Due to a previous 'discussion' on another board I am undertaking a race car project - two actually. My goal is to build a TGP and a T code as high as I can get em, the TGP of course a W body and the T code in a J or N body. I was trying to get base flow numbers before I cracked open the grinder case. In all cases I am trying to keep the EFI. Having Tom aware of this will be a boon, he did a lot of the pioneering work for AFR and should be able to guide me -these race cars will not be pollution legal or most likely streetable - with a 7000rpm redline using milled 'pink' v8 rods and the proper comp cam, it wont idle, run brakes, AC etc
----------------------------------------------------------------------------------
Notes:
1: the 390 sounds tiny, but for a 3L engine, its more than proper, in some classes, 390cfm is the max carb allowed as is 9.5:1 comp ratio and these guys are north of 700hp with basically 350 cube motors. a 390 will be more than adequate for a carb setup
2: the guy has a tool that screws onto the stud and you adjust a wheel that pushes against the opposite side of the head and opens the valve. You just measure how much you depressed it.
3: at .500 the heads have some serious coil bind[4]....it cant be done, you need to machine the heads to have a pocket to take roughly a 1.38ish spring - but u should get over .550 lift if you do such, there appears to be room.
4: we removed the stock valve spring and installed a spring from a ford AOD tranny 4th gear servo lol. Neccessity is the mother of invention.
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