im replacing my ford truck as its just not big enough no more.....kids are getting bigger and i have to travel farther now to the race track.....the old ford has given me 6 good years of trouble free service....

im replacing it with an older 70's to mid 80's 454 bbc dually 4 door truck.....

laying out the plans for the 454 to increase mileage and and low end torque....

Q i have is about headers......does anyone know who makes the smallest primary headers that have the longest primary's? and can youhelp point me in the direct of a supplier with price.

My boss has a mid 80's 4 door dually with a 454 that we use to tow all kinds of stuff. It's got some Hooker headers(not sure what size), a Performer cam, and a Performer intake. It's got some balls, you can just leave it in drive and tow a 16' enclosed trailor with a 5,000lb. car in it. I think it only gets about 10mpg unloaded, and even less loaded with a Q-jet. Were switching to a spread bore Holley soon.

Dennis,sounds like a great idea for "tow truck"
I bet a 650 spreadbore v/s Holley on a Performer intake would be perfect for gas mileage.
I don't know about headers other than the $86 Summit brand that fit a truck application.

Just put a HT502 crate motor in it and everything in the world will be OK. A friend did this and we could not believe the difference. He actually got much better mileage, too.

But if that's more than you wanted to spend, then a some Thorleys (headers) should make a noticeable improvement. The tri-y design allegedly adds to low and mid-range torque. They've been the "hot" setup on these trucks for many years.

I have Hedman Elites on my '76 C20 and like them quite a bit, too. It was between them and the Thorleys for me, but I went with the Hedmans for the prettier welds.

Hope this helps!

i have been checking out ebay for a spreadbore carb and i was going to put a holley on it......i was going thru my holley book looking for the smallest primary throttle blades and i was really surprised how small a 4 bbl can be.....there are some as small a 280 cfm! for a 4bbl carb! i was thinking between a 450 spread bore and the 600 something.....to put on the motor......holley i know how to build and tune to perfection....thats why im going to put one of them one over the Q-jet.


i'm not going to drop that kinda money into the truck for a 502......lol.....that would be a bigger engine then the race car and my z28....lol

i was thinking of the tri-y headers or the after burners......but thought i would check here if maybe by chance someone was doing or done the same thing i was thinking of......

the 454 wont need much carb for maybe it might see over 4000 rpm......it wont be a hot rod just built for torque......

thanks for the input so far.....this is going to be a nice gift from uncle sam this year......i just love income tax returns.......lol

Whatch out for some of the spreadbore Holleys they are a different breed than the 4150 style, reverse idle circuits, different fuel bowls and metering blocks, different gaskets. I'd dump the spreadbore idea and go with a basic 1850 holley 600. Your 454 won't need dinky primary throttle blades, and I bet mileage will be as good or better with the 4150 style carb once it's tuned. Bob

You'll need at most 525cfm per Holley's own formula if you've got 454ci and are only going to 4000RPM and you're at 100%VE.

90%VE= 475cfm
85%VE= 450cfm
80%VE= 425cfm

I rounded up on the high side (about 5cfm more than the formula suggests).

I'll keep my eye open.....i would maybe go with a square bore but just to keep things simple i'm going to install the spread bore on the stock intake......so there is no need to run my adapter plate......i have a huge listing of the holley carbs so i can check to see if they are the reverse idle mixture screws and so forth.....more then likely i will run a 650 spreadbore.....there prim. throttle blades are 1 3/8" with 2" secondaries........a 450 spreadbore has the same prim. size blade of 1 3/8" but the secondary's have 1 7/16"........when you compare that to say the 500 2bbl carb they have 1 11/16" blades.......and the 600 has 1 9/16" blades..........

the 650 seems to fit the bill.....small ventura and larger one out back for maybe if they are needed......i think there might be a smidge better chance of fuel savings over the larger 1 9/16" blades on the 600 carb....

there will be alot of tunning to get this right and hope this little homework pays off....

thanks slowpoke......im sure i can rule out 100 percent VE......lol.......so it looks like the 650 spreadbore would sure be a better chioce then the 450 spreadbore.......for just incase i want to stomp the gas.....lol.......im kinda guessing the prim. side of a 650 flows about 125 to 150 cfm's....because the secondary's are bigger then a 500 cfm holley 2 bbl carb......500 2bbl is showing 1 3/8" ventura with 1 11/16" blades and the secondary's on a 650 spreadbore are 1 3/8" ventura with 2" blades......

i really think those smaller primary's will give me a good chance to achieve some mileage.....

The very best header that you will find for your application is Hooker #2826. These have 1 7/8" tubes, 35 inch primary length and 3" collectors. These headers will be somewhat more expensive than Summits and other brands, but you will not find an "inexpensive" header with tube length anywhere near 35".
Use an "H" pipe, good quality turbo mufflers and stock tailpipes for a good sound.
Holley 650 cfm with vacuum secondaries on the stock manifold with a Mr. Gasket heat shield and a good air cleaner. RV cam, lifters and springs (delete the valve rotators, if so equiped) will really help this engine, too.
Install and adjustable vacuum advance on the HEI then do some serious carburetor and ignition tuning - you will be set to go.

The 391 FE motor in the old F-750 straight truck I used to drive had a 390cfm Holley 4-barrel on it. But it was governed to about 3,500 or so max. rpm!

pdq67

as an owner of a 3/4 ton dodge with a V10 that gets 9 mpg city/14 highway, I would recomend you look into a truck with a 6.2 6.5 diesel. They are not too bad with the banks sidewinder kit.

thanks for the reply's guys......as far as the diesel....uh...i dont think i will be going that route....they maybe better for torque and gas mileage but im not a big fan of them.....i have more then my fair share of bbc parts so if it was to ever break down it would be far cheaper to fix at that given moment....in the long run i may spend more on the bbc as fair as gas goes over a diesel but the initial cost will be way cheaper for what im doing and i think i will have more truck for the money that will be spent....if the truck would be used for day in and day out useage for hauling then maybe a diesel would be the best choice but for just the few times a year i go to the track its not needed.....

thanks for the header part number i will have to check into those......not to gitty about the 1 7/8" tubes but maybe they will be ok with a longer 35" tube......i have some bbc headers i might have to go measure those and see what length they are.....i'll be using a 650 carb but it will be a spreadbore design for sure.....cam i will give more thought...i was thinking of the 200- 2teen range at .050"......i do have a 214/224 @ .050 cam i thought about using since i do have it but im thinking it might be to much.........what do you guys think?

went out and measured a header for a bbc camaro it the shortest was about 20" and the longest tube was about 33"

Holley made a quadrajet replacement carb for the 454 called an economizer, I may get a slap for this but I really had good luck with these carbs in a daily driver, good power clean and crisp on a stock type engine IMO. A much better idle and power circuit than the vacume secondary and mecanical secondary spread bore Holleys.

Cool, I understand, I also dislike diesels and that is why I bought my V10. I do think my V10 would get better mpg is I disabled the EGR. Also, the fuel injection is not sequential, which means it dumps fuel in the cylinder on compression and exhaust. With the right combination I think you could manage 12 mpg city 16 highway if you really watch the timming. What is going to kill you is you can't put any compression and timming in the vehicle because of the weight of the vehicle, or thats what I think.

well i sure was going to bump the compression up with a set of steel shim head gaskets it will give me about a .5 boost........the hei unit sure will be fine tuned.....to bring in the max amount of timing it will take........i have a pretty good idea i might have to buy a timing adjuster one of those dial controls to play with for towing.......the truck my not like a lot of timing while i tow with a load.....but only time will tell.......i'll set everything up for gas mileage and torque and if i have to make a few adjustments for towing i will do so and find the happy medium to make it complete package........


i now have been toying with the idea of gears that will be needed....and right now im looking at 3.08 gears.......my thinking was that i was wanting to run about 2200 rpms at 65 mph........i think anything below this would be to low....with 3.08 gears in drive depending on my tire size and amount of convertor slippage im looking at around 2300-2500 rpms i will end up with running 3.08 gears......i think this will be plenty to run down the road.......thinking anymore rpm is just extra wear on the motor......i see no reason to spin the motor above 2600 rpms to move down the road at 65 or 70 mph.....i know i loose a lot of mechanical advantage running 3.08 gears say verses 3.73 or 4.XX. but i dont think there would be enough offset (gas wise) for the highway drive to the race track so to speak to rely need the extra(more) gear.......

whats your thoughts on this guys?.......remember guys this truck wont see a lot of towing maybe once or twice amonth to the track...it will live most of it's live as the family truck to haul the kids to sports and haul stuff for friends every now and then......

I like the idea of a timming controler, but reconsider your gears. 3:55s are probably the min. Your dealing with a vehicle that weighs 7000 + lbs, and just from driving my truck it pings going up slight hills and it has less than 8.01 compression and 3:55 on 85 octane(colorado). To remedy the problem I just turn off the overdrive before I go up certain hills. When towing my chevelle my truck would ping itself to death with the overdrive on. Consider why 1 ton trucks come with 4.10s standard.

If you are going with a dually, your choices of gears is very limited. I think that 3.73 and 4.10 are the only gear sets available for this rear end. For the past few years the C3500 dually truck has 4.10 gears standard and 3.73 optional for the 8.1L engine. Duramax diesel equipped trucks have 3.73 as standard and 4.10 as an option.