opionions on a repower

[swamp_beast]

so ive decided that the old 454 in my gmc is about ready ready for a rebuild or a whole new engine as i have also been tinking about using the ls5 for a 67 impala so here are a couple options i have. i have a complete low miliage 1970 caddy thats to rusted for resto that can donate its engine i also have acess to a complete 2000 454 with trans harness and accesiries for 2500 so id like opinions should i fork out the cash for the efi 454 and go through all the work to make it work in my 76 should i swap in the 472? or just rebuild what i have in there and continue the long process of trying to find a good 454 core for the impala. big block engines are worth a premium it seems around here as they are a bit rare what type of mpg advantages are there ect ect. any and all opinions are welcome

 

[chilliwak]

If you want good mileage go with the late model engine. If you want ease of swap go with another 454. Larry on the forum here can give you lots of info on tbi conversions. Keep us up to date with whatever you do and please post some pics of your rig... Cheers, Chilli.

 

[swamp_beast]

yea if i was going fuel injection id just go all the way with the efi 454 from my buddies 2000 3500 as its complete ready to rock but would take alot of work to convert my 76s electrical system to run it as well as the fuel tank he said with his truck saw around 12 city 14 hwy on a crew cab 4x4 but would actually be a down grade in the power department the caddy is actually the most potent option as far as torque goes and doesnt reguire to much as far as swapping it except getting the 4l80 to run behind it. now the caddy was getting a best of around 16 mpg with the standard 3 speed auto in the 5,000 pd sedan deville its currently sitting in now i remember 10 years ago caddy swaps into gm trucks was big but i cant seem to find many people that are still running one and thier opinions on the caddy swap

and to clarify on my statement on the power remark the 2000 454 from my research makes 295 hp 410 pdft
the caddy in current state makes 355 hp and 525 pdft my current 454 makes 345 hp and 480 pd ft or did make when it was in its prime over 400,000 kilometers ago

 

[TooTall'sTruck]

I had a 1969 Caddy in high school....biggest mistake was selling it! I would go with the 472 in a heart beat. My friend had a warm 454 in his dually and it got 4 mpg no matter what, the 472 was much more effecient and powerfull. There is a great website for the Caddy big blocks, a little google should find it, but they were around with a text only page ten plus years ago and they would be able to convince you without a doubt. I do remember that the Edelbrock intake for the 472 was a huge inprovment because GM lowered the intake towards the oil pan to clear the low hoods of the caddilacs and the edelbrock rises it up 2-3 inches and flows alot better. The site that was around for at least a decade was www.500cid.com

I will see if I can find some old info/pics to help you decide to go with the 472....I do remember the valves started to float around 4200 RPM (well past usable power)but the only time I ever got there was with my "tire Fires"!!

 

[swamp_beast]

yea i was talking to a guy from cad500 company he swears about a grand and my 472 should clear 400 hp and 550 pd ft all below 3,200 rpm and hit 14 or 15 mpg in my application almost sounds way to good to be true and thought he maybe just one hell of a salesman and selling me some smoke

 

[TooTall'sTruck]

I would think it would be possible, I think my plan was a camshaft, intake, single 4 barrel and exhaust...IIRC the factory headers flowed enough untill you really got higher RPM and HP.

 

[NOIBN]

The bell housing bolt pattern of the caddy is different than the Chevy pattern so you will have to deal with a transmission swap too with the caddy motor.

 

[1leg]

If you need more power then I would go with the CADDY motor. In my opinion the best towing gas motor ever built was the 472/500 inch CADDY motor. If you want something simple you could swap the intake on your buddies 454 to a q-jet manifold and have a fresher motor.

 

[swamp_beast]

yea i know about the needed adapter but i was planning on dropping the th400 and going with a 4l80 and np241 combo or a 205 if the 241 cant survive if i go caddy i should be able to keep the 4.11 gears with the 37s as well

 

[RoyJ]

yea i was talking to a guy from cad500 company he swears about a grand and my 472 should clear 400 hp and 550 pd ft all below 3,200 rpm and hit 14 or 15 mpg in my application almost sounds way to good to be true and thought he maybe just one hell of a salesman and selling me some smoke

550 lb-ft I'd believe, with really good intake/headers/exhaust, and whatever cam they throw in there. 400 hp @ 3200? No way in hell!

Simple math says you need 656.5 lb-ft at 3200 rpm to make 400 hp. That's way beyond the technology of those old big blocks. Hell, my LS7 would have trouble making that much torque per cube, with much higher volumetric efficiency than a 472.

 

[1meanz]

I'd go with the caddy. Better off idle torque and midrange than the 454.

 

[98dango]

Of your options caddy all the way. the best motor next to an.8.1.

 

[warwgn]

speaking of 8.1, why not just stroke and bore the 454 to a 496? That is what I did and it has the Q-jet 800 on an edelbrock performer intake, and it has stupid power!!! not sure on gas milage yet but I can eaisly walk away from my wifes Camaro, which is only a v6, but still this is in a 3/4 ton Suburban TH400/208 4.10 gears and 37's. I am very happy with how it runs, I was expecting stump/camper pulling power but the hot rod accelration caught me off gard. It has been a long time since I was on the drag strip, but I would bet I am in the low 14's and if I could control wheel spin (yes wheel spin) I think I could get a 13 in front of the .

I might be off like I said, but it flat out gets it when I drop the skinny pedal. I am built up a little more than what most would do but not radical by any stretch. Just saying for power dont count out a worked over big block, and to make it a 496 is not that big of a deal, just need an older block that is still think and taking it .060 over is just fine, then a stroker crank and rods and your making lots of power!!

 

[swamp_beast]

well looks like the wife has made the decision the 454 will be getting bored and stroked as per warwgn suggestion but will end up in the 67 impala the wife adored the old caddy and says it should live on and so it shall. tourqasuarus as my wife called it will be the new powerplant for the suburban plus my wife has a strangle hold on the money and says i dont need any more toys ********

 

[1meanz]

she is a wise woman. looking forward to the "tourqasuarus" build.