I've got a 1970 Cougar with a stock 351W with a 2bbl carb. I'd like to eventually replace the heads, intake, carb, and cam. but, if I do this in phases (father/son project) is there enough benefit to just switching the carb and intake first?
2bbl to 4bbl
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Just do it all in one shot to truly appreciate the large increase in power.
f it doesn't already have headers and a free flowing 2¼-2½" exhaust system, make that mod first... Will really wake up a 4-bbl install... Also 351 heads for '69-'71 are fairly decent(a bit of a rarity for Ford), later GT40 iron heads were patterned after the original 351W head...
But if you really want to get some power go aftermarket heads, I run the Twisted Wedges on a 5.0, difference was night and day...
But if you really want to get some power go aftermarket heads, I run the Twisted Wedges on a 5.0, difference was night and day...
My first mod was changing out a carb and intake on a 77 Buick. It was pretty easy to do so it was a good first step for me to get my feet wet.
I don't know how much experience you have doing engine mods but the intake and carb is a good first step if you're not experienced. As to how much difference you'll feel, I don't know.
I don't know how much experience you have doing engine mods but the intake and carb is a good first step if you're not experienced. As to how much difference you'll feel, I don't know.
It's a great first step. Followed by free flowing dual exhaust. Or vice versa. Enjoy the Cougar, I owned a few 70 Cougars once upon a time!
thanks for the feedback! I had read that the factory heads of that era were pretty good. actually, I have had the car since 1992. stopped driving it in 1998. just pulled it out of storage - my son is very interested in beefing it up.
Originally Posted By: tomcat27
I've got a 1970 Cougar with a stock 351W with a 2bbl carb. I'd like to eventually replace the heads, intake, carb, and cam. but, if I do this in phases (father/son project) is there enough benefit to just switching the carb and intake first?
What size carb? Optimally, you'll need one size for the otherwise stock engine, another for the finished product.
I've got a 1970 Cougar with a stock 351W with a 2bbl carb. I'd like to eventually replace the heads, intake, carb, and cam. but, if I do this in phases (father/son project) is there enough benefit to just switching the carb and intake first?
What size carb? Optimally, you'll need one size for the otherwise stock engine, another for the finished product.
Originally Posted By: HangFire
Originally Posted By: tomcat27
I've got a 1970 Cougar with a stock 351W with a 2bbl carb. I'd like to eventually replace the heads, intake, carb, and cam. but, if I do this in phases (father/son project) is there enough benefit to just switching the carb and intake first?
What size carb? Optimally, you'll need one size for the otherwise stock engine, another for the finished product.
2-bbl carbs tend to have pretty big venturi's, 450 or 500 cfm.
A 4-bbl of almost any size should have smaller primary venturi's which can improve fuel consumption for as long as you can keep your foot out of it.
A 650 cfm 4-bbl and a dual-plane manifold will offer good low end torque up to around 5,000 RPM and be nice and drivable on the street. You lose top end above 5K but not much. Without valvetrain mods and an aggressive cam, it will be fine.
You need cam to use a 750 or 850, and anything larger (1150 Dominator) is race only.
You can go bigger if you use a spread-bore carb, but Fords are traditionally Holley territory, which is a 4 identical venturi design.
I know the magazines always use big carbs, but they often showcase builds that are about big HP numbers rather than practical street motors; if a bigger carb shows 20 more HP, they run it. But it's a bigger mistake to over-carb than under-carb, and it's way more fun to drive a motor with more torque "area under the curve" than higher RPM peak torque.
Originally Posted By: tomcat27
I've got a 1970 Cougar with a stock 351W with a 2bbl carb. I'd like to eventually replace the heads, intake, carb, and cam. but, if I do this in phases (father/son project) is there enough benefit to just switching the carb and intake first?
What size carb? Optimally, you'll need one size for the otherwise stock engine, another for the finished product.
2-bbl carbs tend to have pretty big venturi's, 450 or 500 cfm.
A 4-bbl of almost any size should have smaller primary venturi's which can improve fuel consumption for as long as you can keep your foot out of it.
A 650 cfm 4-bbl and a dual-plane manifold will offer good low end torque up to around 5,000 RPM and be nice and drivable on the street. You lose top end above 5K but not much. Without valvetrain mods and an aggressive cam, it will be fine.
You need cam to use a 750 or 850, and anything larger (1150 Dominator) is race only.
You can go bigger if you use a spread-bore carb, but Fords are traditionally Holley territory, which is a 4 identical venturi design.
I know the magazines always use big carbs, but they often showcase builds that are about big HP numbers rather than practical street motors; if a bigger carb shows 20 more HP, they run it. But it's a bigger mistake to over-carb than under-carb, and it's way more fun to drive a motor with more torque "area under the curve" than higher RPM peak torque.
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Choose a 4-bbl that is either small overall, or has vacuum secondaries so that it won't "over carb" the engine, and you can do the carb/intake as a first step. Then it will accomodate later changes without having to do a massive re-tuning.
My personal favorite is the Carter AVS (available new as the Edelbrock Thunder Series) but the new ones are admittedly pricey. Never have liked Holley because of the fact they use diaphragm accelerator pumps, but they do offer more choices and great aftermarket support.
My personal favorite is the Carter AVS (available new as the Edelbrock Thunder Series) but the new ones are admittedly pricey. Never have liked Holley because of the fact they use diaphragm accelerator pumps, but they do offer more choices and great aftermarket support.
Carter AVS is definitely a good place to be. Real easy to tune and set up. Not nearly as accurate as a good Q-jet, but not a bad carb, and a good performer.
Originally Posted By: Johnny2Bad
2-bbl carbs tend to have pretty big venturi's, 450 or 500 cfm.
A 4-bbl of almost any size should have smaller primary venturi's which can improve fuel consumption for as long as you can keep your foot out of it.
A 650 cfm 4-bbl and a dual-plane manifold will offer good low end torque up to around 5,000 RPM and be nice and drivable on the street. You lose top end above 5K but not much. Without valvetrain mods and an aggressive cam, it will be fine.
WOW things must be bigger up in CA, I've never seen any factory Ford 2bbl carb that was more than 350CFM(were used on 390 & a few 429)and most were more like 270-300CFM...
Back in the day, Ford 1969 Ford Muscle Parts recommended a 600CFM for the 351, 625-650 is max for a mild performance street package... Bigger performance carbs are just that, for bigger engines... We aren't talking a over 400cu in engine, or huge volumetric efficiency...
2-bbl carbs tend to have pretty big venturi's, 450 or 500 cfm.
A 4-bbl of almost any size should have smaller primary venturi's which can improve fuel consumption for as long as you can keep your foot out of it.
A 650 cfm 4-bbl and a dual-plane manifold will offer good low end torque up to around 5,000 RPM and be nice and drivable on the street. You lose top end above 5K but not much. Without valvetrain mods and an aggressive cam, it will be fine.
WOW things must be bigger up in CA, I've never seen any factory Ford 2bbl carb that was more than 350CFM(were used on 390 & a few 429)and most were more like 270-300CFM...
Back in the day, Ford 1969 Ford Muscle Parts recommended a 600CFM for the 351, 625-650 is max for a mild performance street package... Bigger performance carbs are just that, for bigger engines... We aren't talking a over 400cu in engine, or huge volumetric efficiency...
The only good thing about the Ford 2 barrel is ease of servicing,otherwise they are about as "performance" as a 1 barrel.Notice why Ford went to MPI seemingly before anybody else did and the 302/351 went Holley 4 barrel in the 1980s.Shame they put that 2 barrel in engines from 221 V8s thru 390s/400s....
That size motor cant breathe any more than ~500 cfm at 110% volumetric efficiency. Having (re)done this kinda tune dozens of times after kids did it wrong, I would definitely go with opening up the exhaust a bit with 2 1/8 tailed duals and a H pipe. I would SERIOUSLY consider using a nice "pro-jection-style" 2V TBI setup. I don't know many good carb tuners and the good ones are not cheap and not interested in working on this car. Otherwise, a fresh 600cfm Holley 0-80457 on a 2 plane for intake. If you can stick with factory dual plane AND avoid Edel-Broke, Youll be good. Ford has some good Marine engine perf parts.
Cam? No hotter than ~ 205deg duration, possibly use a short track, tight lobe center cheater - say 108 splay. Can you say Lunati?
Don't ignore the ignition. This is where your power will be made or lost.
So:
Timing set, mild cam (not CRANE), uncorked exhaust, Weiand Stealth (or equivalent) dual-plane, EFI or Holly ford 600cfm carb. This is all under 1500 bucks.
The you can look at a sloppier converter and a Locker rear
Cam? No hotter than ~ 205deg duration, possibly use a short track, tight lobe center cheater - say 108 splay. Can you say Lunati?
Don't ignore the ignition. This is where your power will be made or lost.
So:
Timing set, mild cam (not CRANE), uncorked exhaust, Weiand Stealth (or equivalent) dual-plane, EFI or Holly ford 600cfm carb. This is all under 1500 bucks.
The you can look at a sloppier converter and a Locker rear
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ARCO is exactly what I was thinking BRILLIANT!
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Originally Posted By: ARCOgraphite
a fresh 600cfm Holley 0-80457 on a 2 plane for intake. If you can stick with factory dual plane AND avoid Edel-Broke, Youll be good. Ford has some good Marine engine perf parts.
Cam? No hotter than ~ 205deg duration, possibly use a short track, tight lobe center cheater - say 108 splay. Can you say Lunati?
Don't ignore the ignition. This is where your power will be made or lost.
So:
Timing set, mild cam (not CRANE), uncorked exhaust, Weiand Stealth (or equivalent) dual-plane, EFI or Holly ford 600cfm carb. This is all under 1500 bucks.
The you can look at a sloppier converter and a Locker rear
There you go, sounds almost like the 306 in my '72 Comet...
Has a Lunati Voo Doo 207*/213* cam, 600 Holley(was free, sent a defective one back to Holley that a freind gave me), Weiand intake on a set of Pro Comp heads & Thorley headers... Exhaust is 2¼" with Magna Flow mufflers... Disty is a Ford Duraspark triggering a Street Fire ignition... The Dist, Street Fire box, wires, dist cap, etc was $60 buy from a member on the Maverick/Comet Forum..
The fresh built C4 is stock(prob swap to AOD) but does have a Hughes 2200 converter... Biggest problem, on regular radials traction is almost non existent...
Don't pay attention to the plug wires, going to cut my own using the black Ford racing wires...
a fresh 600cfm Holley 0-80457 on a 2 plane for intake. If you can stick with factory dual plane AND avoid Edel-Broke, Youll be good. Ford has some good Marine engine perf parts.
Cam? No hotter than ~ 205deg duration, possibly use a short track, tight lobe center cheater - say 108 splay. Can you say Lunati?
Don't ignore the ignition. This is where your power will be made or lost.
So:
Timing set, mild cam (not CRANE), uncorked exhaust, Weiand Stealth (or equivalent) dual-plane, EFI or Holly ford 600cfm carb. This is all under 1500 bucks.
The you can look at a sloppier converter and a Locker rear
There you go, sounds almost like the 306 in my '72 Comet...
Has a Lunati Voo Doo 207*/213* cam, 600 Holley(was free, sent a defective one back to Holley that a freind gave me), Weiand intake on a set of Pro Comp heads & Thorley headers... Exhaust is 2¼" with Magna Flow mufflers... Disty is a Ford Duraspark triggering a Street Fire ignition... The Dist, Street Fire box, wires, dist cap, etc was $60 buy from a member on the Maverick/Comet Forum..
The fresh built C4 is stock(prob swap to AOD) but does have a Hughes 2200 converter... Biggest problem, on regular radials traction is almost non existent...
Don't pay attention to the plug wires, going to cut my own using the black Ford racing wires...
A 351w can't breath well.Holley makes a 500cfm 2bbl.that way you can keep your existing manifold.may need a spacer to get the butterfly's to clear. A 351c breathes much better and can utilize a 4bbl better than a w can
I would just pull the heads and get hardened valve seats installed. I second the recommendation on Weiand and Edelbrock carb combo.
Single plane intake, 750 Edelbrock AFB carb and shorty headers.
Your valve springs are 45 years old don't forget.
Your valve springs are 45 years old don't forget.
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