port sizes

I am looking to build an engine for a Factory 5 Cobra. I have a 1970 429, it had a 4bbl carb and dove heads on it, but 2 bolt mains. I assume it is a Thunderjet, but would like to be sure. Looks like the Performer 460 is pretty much the intake that will fit under the hood, but Edelbrock says it will not work with CJ heads. Most of the aluminum heads I look at have ports for CJ intakes and headers, raised ports are offered, is that just a raised floor? Most spec a CJ header. Factory 5 supplied the stainless headers for the 429, but how do I know which ports they will fit? The Edelbrock Performer RPM has a taller pad, and shaped for a spreadbore. Thinking maybe a stroker, seems like everyone suggests to go to a 460 crank minimum, so if I'm buying a crank and pistons anyway, why not a few more inches? Like to keep it streetable, lumpy idle (some) but good low rpm torque. Carbed. Hydraulic cam, maybe a roller? Appreciate the help. Save me from buying parts that don't match? Thank you!

I know you wont want to hear this and I can't believe that I'm actually saying it but have you thought about just sticking with a small block or coyote or cleveland or ??? In a 2200lb car a high torque low rpm big block is just gonna destroy the tires without moving an inch. Also all of that front end weight is gonna throw off the weight balance in the car. If you do go the big block route what trans would you use? Just my .02

lvhdude wrote:I am looking to build an engine for a Factory 5 Cobra. I have a 1970 429, it had a 4bbl carb and dove heads on it, but 2 bolt mains. I assume it is a Thunderjet, but would like to be sure. Looks like the Performer 460 is pretty much the intake that will fit under the hood, but Edelbrock says it will not work with CJ heads. Most of the aluminum heads I look at have ports for CJ intakes and headers, raised ports are offered, is that just a raised floor? Most spec a CJ header. Factory 5 supplied the stainless headers for the 429, but how do I know which ports they will fit? The Edelbrock Performer RPM has a taller pad, and shaped for a spreadbore. Thinking maybe a stroker, seems like everyone suggests to go to a 460 crank minimum, so if I'm buying a crank and pistons anyway,  why not a few more inches? Like to keep it streetable, lumpy idle (some) but good low rpm torque. Carbed. Hydraulic cam, maybe a roller? Appreciate the help. Save me from buying parts that don't match? Thank you!

A "Torquer II" single plane manifold will fit CJ port heads and you can actually put a spacer on the carb pad and it will still go under the hood.

A 460 will have more torque than you will ever be able to use productively; (how far can you spin the tires). A 501 with a 4.150" stroke, with better rods and smaller rod journals is absolutely more than enough for a Cobra Kit Car.

Call FF and ask them what port their headers fit... The next idea would be either to just measure them or buy some header gaskets and see what fits. In all honesty, a 460 with a ported DOVE head would make more then enough power. I have a FF Mk 3 and it weighs around 2100 # with a 4.6 DOHC. AT 320 hspr it is enough to send you sideways if you are not careful. I have a friend with a 460 in his and he has done some "unexpected" donuts in the middle of the highway.

Have you looked on the FFR website? I did a quick search and there are 460 header posts there.

https://www.ffcars.com/forums/big-block-roadster-builds.46/

wickettoby1 wrote:I know you wont want to hear this and I can't believe that I'm actually saying it but have you thought about just sticking with a small block or coyote or cleveland or ???  In a 2200lb car a high torque low rpm big block is just gonna destroy the tires without moving an inch. Also all of that front end weight is gonna throw off the weight balance in the car. If you do go the big block route what trans would you use? Just my .02

Weight is part of the reason to go aluminum heads, as well as standing a little more compression, the coyote is pretty wide, Clevlands are rare and IMHO, just short on C.I.s. I just like to be a little different, and I like the look and sound of a BB. FE's seem a bit tech challenged and I have several 385 series engines to play with, have the headers and mounts, Quik Time steel bell, and a McCloud clutch, PP, and flywheel for the 385 engine.

I have put together a T-5 with Astro gears, and input, that I think will handle street use in a car as light as the FF roadster.

from rmcomprandy "A "Torquer II" single plane manifold will fit CJ port heads and you can actually put a spacer on the carb pad and it will still go under the hood.

A 460 will have more torque than you will ever be able to use productively; (how far can you spin the tires). A 501 with a 4.150" stroke, with better rods and smaller rod journals is absolutely more than enough for a Cobra Kit Car." [/quote]

I was thinking a dual plane manifold might be a bit more streetable, good to know a Torquer would fit, 501 sounds like a plan. H-beam or I-beam? Any real need to 4 bolt the block? Have head or cam reccomendations for a low RPM torque monster? T-5 trans with 3.55 gears in an 8.8, 26" tires. Thanks!

jasonf wrote:Call FF and ask them what port their headers fit... The next idea would be either to just measure them or buy some header gaskets and see what fits. In all honesty, a 460 with a ported DOVE head would make more then enough power. I have a FF Mk 3 and it weighs around 2100 # with a 4.6 DOHC. AT 320 hspr it is enough to send you sideways if you are not careful. I have a friend with a 460 in his and he has done some "unexpected" donuts in the middle of the highway.

Have you looked on the FFR website? I did a quick search and there are 460 header posts there.

https://www.ffcars.com/forums/big-block-roadster-builds.46/

I looked at the FF forum, most everything I found was small block stuff, I called FF and left a message, seems they are short staffed. Thanks!

lvhdude wrote:I am looking to build an engine for a Factory 5 Cobra. I have a 1970 429, it had a 4bbl carb and dove heads on it, but 2 bolt mains. I assume it is a Thunderjet, but would like to be sure. Looks like the Performer 460 is pretty much the intake that will fit under the hood, but Edelbrock says it will not work with CJ heads. Most of the aluminum heads I look at have ports for CJ intakes and headers, raised ports are offered, is that just a raised floor? Most spec a CJ header. Factory 5 supplied the stainless headers for the 429, but how do I know which ports they will fit? The Edelbrock Performer RPM has a taller pad, and shaped for a spreadbore. Thinking maybe a stroker, seems like everyone suggests to go to a 460 crank minimum, so if I'm buying a crank and pistons anyway,  why not a few more inches? Like to keep it streetable, lumpy idle (some) but good low rpm torque. Carbed. Hydraulic cam, maybe a roller? Appreciate the help. Save me from buying parts that don't match? Thank you!

With that light vehicle, use an Edelbrock "Torquer II" intake manifold with a Jomar "Powercone" spacer. You will have plenty of hood clearance with whatever air cleaner you wish to use.

Put a big cam in it as low speed torque will not be an issue.

The former Ford Racing "Cobra Special" 514, M-6007-E514FT, was a perfect fit for a "Superformance" kit car.