I'm planning a build up on a 454 bbc and need help with the plans as I know nothing about big blocks, I'm only experenced with small blocks.
So any help or advice u could give me about cam sizes, heads, intakes etc... would be a big help. I want to use my 750 mech sec. speed demon carb on the motor though (currently on my 406 sbc).

 

Well, I won't talk you out of it. But there are a whole lot of issues to deal with. Look at it this way, your average bigblock will add 120 lbs minimum to any car. A really good one will put out about 650 hp without too much trouble (solid roller and real stout heads). But, you can get within 100hp of that with your 400. Add nos and what bigblock.

But, if you have your heart set on it. Get a set of dart heads. The round port would probably work better with the 750 (you really need close to 850+). And start with 454 cubes. Get 502 if you can afford it.

Get a hydroller cam if you can. Something around 240 degrees intake at 050". You should be able to run a holley strip dominator intake. The performer rpm is a good second choice for about 6000 max.

I would not worry about reusing your 750. Your going to spend soo much money that 750 won't mean squat.

Stephen can probably help more.


[This message has been edited by jcb999 (edited July 10, 2001).]

 

Actually there are a few of us here with big blocks. It's not hard to do the conversion but don't expect it to be an easy drop-in. Using factory exhaust manifolds will be the easyest way. Getting Hooker Supercomp headers needs some frame, crossmember and body modifications to get them to work and since you're probably going to use it on the street, an exhaust system will have to be custom fabricated.

For a street car 400 HP is still within handling limits. A mild big block and easily make 400 HP and be very streetable. A 400 HP small block is starting to get a little racey.

Large oval port heads is all you need. Factory 781 or 049's are a good choice. Stay away from the peanut port truck heads. They have no performance potential and leave the rectangular port heads for the 600HP race engines. Pick a Compcams Xtreme Energy cam that will suit the rest of the car. I use a XE294H. It needs good headers, intake, gears and a 3200+ converter. Way too much for a street car but A XE268H would be a better choice for a typical street car.

Get a Edelbrock performer intake. The 750 Speed Demon is fine.

Other than that it's just a matter of dropping it into the car. Depending on what accessories are on the engine, you'll need all the big block brackets since SBC brackets won't work.



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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

Get the book called "How to hotrod bbc's". It will give you most of the answers on what/how to build a bbc. As far as putting it into a 3rd gen, most of the info is on my page or just ask. 'Cause like stephen said, a few of us have them.

miles

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88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.11's to follow soon )
www.koolmeister.com

 

Thanks for the help.
My 400 puts out 462 hp 520 ft/lbs at the flywheel. Problem is 400's seem to be very unrelaliable when u start getting some power out of them. Last summer I cracked the block on mine(didn't over heat or go lean) and my friend cracked the heads on his.
Would like to build a big block with at least 550 hp and ft/lbs while being more reliable than the 400. I plan on going all out on the bottom end on the motor.

 

man yall must be pretty hard on them 400s in the great white north
I know a guy who uses strictly stock bottomends and throws 200hp of spray on top. The latest motor has held up fine for a year.

I think 550hp from a 454 will require a pretty stout cam and some head work if your going to start with the factory round (non-peanut) port heads. I mean the 454HO motor uses a small rectangle port (but a real mild cam) and it only makes about 440hp. I think 500 hp would be pretty easy with just a cam change.

[This message has been edited by jcb999 (edited July 12, 2001).]