Power advantage between Ford 351, Mopar 340 and Chevy 350??

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So lets talk about the weak point of 351C 4V cylinder heads...

Port flow balance... Intake flow typically equal to a 426 Hemi.... First ya gotta realize back then flow benches didn't pull the pressure/volume they do these days.... Going off memory the numbers for a 351C 4V head were around 130 CFM @ 3 in/H2O Exhaust flow? Equal to a Volkswagen Beetle... Actually the number I remember is 55CFM...

Back then the expected numbers for a 426 Hemi were in the neighborhood of 140 CFM intake 115 CFM Exhaust...

In order to fit the exhaust into the standard engine compartment Ford make the exhaust turn about 130 degrees in the exhaust port...

The serious racers would slice the outer 3/4" of the head off & furnace blaze on side plates allowing the port to continue upward... Not easy to find anything on the internet cause there have been aftermarket heads almost as long as theres been an internet.... But I found a few pictures so y'all can get an idea of what was involved...

Screen Shot 2022-09-01 at 6.13.00 PM.png
Screen Shot 2022-09-01 at 6.15.10 PM.png



And that is your Ancient NHRA history lesson for today...

Oh, Before he dominated with a 340 with some of the very first W2 heads Bob Glidden was one of the innovators behind side plating Cleveland heads....
 
They would also raise the bottom of the port with a "tongue".
Those Clevo's were pretty good performers here with Touring car racing..

Tongue.jpeg
TFC-FILLER-351C-4V.jpg
 
Bakerlite said:
They would also raise the bottom of the port with a "tongue".
Those Clevo's were pretty good performers here with Touring car racing..

View attachment 1715979456 View attachment 1715979458
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Yup, those worked pretty good, but I'm more about using the whole port and just getting the cam compression and port shape as matched as possible. I think there's power to be made with the port pretty much as is. Ford did too. They were right.
 
And that begs for more Pro Stock fun... As was mentioned earlier.. The rules were continually changing to try to "Level" the playing field.. Read "Level" as "Give GM an Advantage" In the first years of Pro Stock the Hemi was unbeatable... So NHRA kept increasing the Weight Factor per CI on the Hemi till it couldn't compete.... The were guys destroking Hemi's down to 396 CI.. But it was a losing battle...

Grumpy/Rehr & Morrison/Allen... The GM crew was dominating... Then a few guys joined the Ford camp like Dyno Don (who raced Chevies till he saw a loophole) & Bob Glidden cause the weight factor on the 351C was equal to the chevy but the heads had more potential... So the faster the Fords went the more weight NHRA tacked on.... And the Fords kept getting faster in spite of the weight for a few years but eventually the weight penalty was to great... In 78 Bob won the NHRA Pro Stock Championship...

And somehow Chrysler was able to pull Bob off to the side & offered him lots of cool toys.. But more importantly told him NHRA wasn't paying attention to the Mopar small block & they had some new heads that were a game changer.... And Bob liked slipping under the radar due to rules that were behind the curve...

In 79 Glidden showed up with his lil Arrow & dominated... So NHRA tacked some weight on.. & Bob just went faster... In 79 NHRA added weight three times... In 80 Bob showed up again with the Arrow, but three races in he went back to his Fairmont in spite of NHRA's efforts still had a winning season eventually winning the championship for the third straight year...


On another subject oiling system weakness of Ford 351C or most Fords for that matter... True.... But have you seen the mods done to a serious race effort on a small block Mopar to improve oiling?

Plenty of engine have weak points... The guys who find them & fix them are the guys who win races...
 
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Yes, they all have weak points. I'm sorta basing my comments around hopped up street engines..
 
1WildRT said:
So lets talk about the weak point of 351C 4V cylinder heads...

Port flow balance... Intake flow typically equal to a 426 Hemi.... First ya gotta realize back then flow benches didn't pull the pressure/volume they do these days.... Going off memory the numbers for a 351C 4V head were around 130 CFM @ 3 in/H2O Exhaust flow? Equal to a Volkswagen Beetle... Actually the number I remember is 55CFM...

Back then the expected numbers for a 426 Hemi were in the neighborhood of 140 CFM intake 115 CFM Exhaust...

In order to fit the exhaust into the standard engine compartment Ford make the exhaust turn about 130 degrees in the exhaust port...

The serious racers would slice the outer 3/4" of the head off & furnace blaze on side plates allowing the port to continue upward... Not easy to find anything on the internet cause there have been aftermarket heads almost as long as theres been an internet.... But I found a few pictures so y'all can get an idea of what was involved...

View attachment 1715979452 View attachment 1715979453


And that is your Ancient NHRA history lesson for today...

Oh, Before he dominated with a 340 with some of the very first W2 heads Bob Glidden was one of the innovators behind side plating Cleveland heads....
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My buddies engine builder does that with big block ford heads. That is an old police intercepted head he did for a 472 inch 460

F1CB2AED-20AC-44F9-9385-6956C15AE9C6.jpeg
 
1WildRT said:
Along with a 351M... Plus the 351C 2V or the 351C 4V or the Ram Air/ Boss 351

Also depends if it's a LT-1 or a Goodwrench rebuild...

And it depends if it's a 68-71 340 or a 72-73 340 with dished pistons...
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& the la 340 will out run them all the 340 makes way mpre low end torque
 
RustyRatRod said:
I agree about the Cleveland. With ports and chambers like this, the 340 would get left behind at high RPM.
View attachment 1715979031 View attachment 1715979030
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I also had a 70' Cleveland 2bbl in a cougar XR7 and it ran well for such a heavy car. Being a 2bbl my 340 Dart would take it to the cleaners but with a 4bbl. I'm not so sure, being the Dart is lighter, possible. UP & UP, Cleveland is my bet.
 
The biggest issue with the chevy and cleveland was they all needed WAY more gear than the Mopars to run.
 
In May of 1970, CAR CRAFT Magazine ran an article titled 'Econo Racer Test' which pitted the 4 strongest and cheapest performance cars against each other - here's the results:

#1 Duster 340 4sp w/3:91's = [email protected]

#2 Swinger 340 3sp w/3:91's = [email protected]

#3 Nova SS 350 4sp w/4:10's = [email protected]

#4 Mach 1 351 4sp w/3:50's = [email protected]


Then in April of '71, CAR CRAFT ran an article titled 'Drag Comparison' where it put the Demon 340 with the new 850cfm ThermoQuad up against a Hornet 360 and this is what it ran:

Stock form: [email protected]

W/Headers: [email protected]

Lots more 340 information, production numbers etc. here:


https://www.swinger340specials.ca/340-review
 
Woodys_Cuda said:
In May of 1970, CAR CRAFT Magazine ran an article titled 'Econo Racer Test' which pitted the 4 strongest and cheapest performance cars against each other - here's the results:

#1 Duster 340 4sp w/3:91's = [email protected]

#2 Swinger 340 3sp w/3:91's = [email protected]

#3 Nova SS 350 4sp w/4:10's = [email protected]

#4 Mach 1 351 4sp w/3:50's = [email protected]


Then in April of '71, CAR CRAFT ran an article titled 'Drag Comparison' where it put the Demon 340 with the new 850cfm ThermoQuad up against a Hornet 360 and this is what it ran:

Stock form: [email protected]

W/Headers: [email protected]

Lots more 340 information, production numbers etc. here:


https://www.swinger340specials.ca/340-review
Click to expand...
Notice they conspicuously left OUT the 71 BOSS 351 Mustang. They used the Mach 1 instead. I'd like to have seen the difference.
 
I tried to find the original article online but no luck. I wanted to see the criteria, they did mention only 1970 econo cars. Was the 1970 Boss left out because of a higher price point? Was the Mach1 a cleveland engine?
 
Motor Trend got 13.8 out of a 71 BOSS 351 Mustang in 1971.
 
Woodys_Cuda said:
I tried to find the original article online but no luck. I wanted to see the criteria, they did mention only 1970 econo cars. Was the 1970 Boss left out because of a higher price point? Was the Mach1 a cleveland engine?
Click to expand...
Mach1 was a Cleveland. Not all Clevelands were the same.
 
1970, no Boss 351. They were Mach 1's with the windsor or cleveland avaialble IIRC.
 
The LT1 Camaro was neck and neck with the 340, running 14.2 @ 100.
Some tests had the Camaro running 13.9@ just over a 100.
 
Boss 351: 11.7:1 forged pistons and 290* duration solid cam.
LT1: 11:1 forged pistons and 317* duration solid cam

340: 10:1 cast piston 268* duration hydraulic cam...
 
66fs said:
Boss 351: 11.7:1 forged pistons and 290* duration solid cam.
LT1: 11:1 forged pistons and 317* duration solid cam

340: 10:1 cast piston 268* duration hydraulic cam...
Click to expand...
Also, there were many more Dusters, Darts and Demons built with 340s in the years the LT1s and Boss 351s were built. The sources don't all agree on the numbers, but the totals are overwhelming.
 
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