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Cadd 500 motor with 425 intake

the elderbrock is a very good intake and definitly better than a stock intake, esp. taking a stock intake designed for a smaller engine. in the title to your post you state its a 500, is it ??

will one of the other fellas please posta link to the 'www.cadillacpower' site, im not computer savy. thanks guys. :)

you"ll have alot of reading to do when you get to the other web site.take your time.
 
I dont know what Cadillac guys you are talking to. Car cadillac guys offer opinions with no experience in what we do. I can tell you for certain, having built and run Cadillac 500's for 30 years on airboats, direct drive and 4 different gear drives, that the Edelbrock is superior. Across the board. Try them back to back and check it out. Regards, Charles
 
just the extra few pounds in weight savings on a direct drive is worth it to keep the edelbrock.not to mention it will flow out of the box better than if you had to do a bunch of work to the stock intake.the intake was a design out of neccesity for clearance hood and air compressor.the plenum sits so low that the runners angle up.i am sure there are dyno sheets out there that prove the differances.i can only assume the reason these people tell you its better is that they probably run the quadrajet on the stock intake and it performs verry well.this is just an assumption. but imo i think the the quadrajet is the best card for d.d caddy. but this is just my opinion. here is a link to cb7 cadillac power,undoubtably the best caddy big block site on the net.

http://www.cadillacpower.com/forum/
 
I can see a 425 intake working better on a DD because of the flow closer matching a 2800 rpm need and no more. At 3500, it'd be worthless. Should have more snap down low because of smaller cross sectional area too.
 
richard how would the ports on the 425 intake match up to the ports on the 500 heads ? if they are that close then shouldnt this guy just find some heads off the 425 and use those as well to get the bump up in compression. so he will have smaller ports and higher compresion ???????
 
I am a true blue Caddy guy with an Edelbrock intake but on a DD the factory intake workes better. To get the full effect you need to install a 1" divided spacer on the factory intake and you will see more RPM's. I do not think the 425 intake's ports line up though. If you use the 500 stock intake you can attack it with a die grinder to shed a couple pounds. Also hammer a freeze plug into that hole in the bottom of the intake because it tends to hold raw fuel and this causes run on when you kill the motor.
 
The ports line up but they are smaller, so you actually get some reversion protection too. Same engine family, just smaller. The Stock Cadillac BB is designed to run at 3200 rpm or so, so the give enough stock port for ,let's say 3600 to 3800. Same with the 425, so smaller cubic inch manifolds make optimum airflow at low rpms on a bigger engine IMO. It'll be more responsive to get you on plane for sure. How do you guys with DD keep from over turning your props and ultra-sonic killing them. The larger diameter, the quicker they reach the speed of sound per rpm. The shorter the prop, the faster you can turn it w/o the tips exploding. Just curious. I'd guess on a better prop, it's a pitch thing, but what about wooden, non adjustable props? Thanks
 
Right now Im running a 600 holly with eldelbrock intake,, i just cant seem to get pass the dead spot,, i have tried everything i can think of. This is why I want to try the 425 aluminium intake and a Qjet carb.. i have a factory 425 intake and carb,, i want to get the carb rebuilt and install the both and see if it works. I can turn the motor 3100 to 3150 with a 72x34 wood prop.
 
INSTEAD OF STARTING A NEW THREAD ! EVERY BODY SAYS PROP IT AND LET YOUR MOTOR RUN OUT OF THE STRAIN ,WHICH IS UNDERSTANDABLE ! BUT ON MINE ITS SEEMS LIKE ABOUT 4300 ITS HAPPIER THAN AT 4800 ! HARD TO EXPLAIN ! IT EASY TO GET UP TO ! NO MATTER WHAT THE PITCH IS THREE AND UNDER ! NOT COMPLAINING ! IT WILL MOVE NO MATTER WHAT ! JUST OPINONS PLEASE AND RICHARD WELL GET WITH YOU A LOT OF STUPID STUFF HAPPENING WITH THE KIDS THANKS !
 
somedumbredneck":3vkruwyf said:
Right now Im running a 600 holly with eldelbrock intake,, i just cant seem to get pass the dead spot,, i have tried everything i can think of. This is why I want to try the 425 aluminium intake and a Qjet carb.. i have a factory 425 intake and carb,, i want to get the carb rebuilt and install the both and see if it works. I can turn the motor 3100 to 3150 with a 72x34 wood prop.
Click to expand...

I hope you are going to a bigger prop or more pitch because at those rpms you are flirting with over spinning depending on the temp. There are several sites you can go to that will tell you your tip speed when you plug in the diameter of your prop and the air temp. I would never spin a wooden prop that hard unless it was new or was just reconditioned.[/u]
 
Im not looking for RPM Im looking to get over the dead spot.. as soon as it is gone I will change the prop.. And FYI if you got a good wood prop 3000 rpm will not hurt it.
I have spun them 3200 and had them come apart at 2000, thats what you take good care of a wood prop and kep it out of the weather. A good wood prop cant be beat!!
 
DUMB REDNECK , I TOO AM RUNNING A 74 500 CADDY ORIGINALLY IT WAS STOCK GUTS W /EDELBROCK INTAKE AND CARB IT WOULD TURN A 72 36 WIDE BLADE TO 3100 SO I PUT A 72 38 WIDE BLADE THAT KNOCKED HER DOWN TO ABOUT 2800-2900 I NOTICED NO SIGNIFICANT CHANGE IN POWER IVE SINCE BLOWED THE BITCH UP AND HAD TO COMPLETELY REBUILD IT W/ NEW CRANE CAM. HOOKED HER UP TO A 3 BLADE SENSENICH AND WITH THAT COMBO SHE'LL RUN DRY WITH THREE GUYS VERY PLEASED.
CADDY POWER BABY !!!
 
Just something u guys may find helpful.

If u care for @ numbers... tip speed in ft/sec = 0.00436 x ( prop length in inches ) x RPM

Metal props can go up to 1000 ft/sec before losing thrust

Wood props can got up to 900 ft/sec before losing thrust

Composites are a compromise between wood and metal props depending on tip design, i.e. blade thickness approaching the tips.


Note: those figure would be very loud and very high tip errosion effect. 700 to 800 ft/sec is a good compromised figure for noise signature. 500 to 600 ft/sec would be great for noise factor ( not ideal for small props ).


As for RPM targets, most props, if high pitched: static rpm = 0.9 x top running rpm

ex. if target RPM is 4800, then static rpm = 0.9 x 4800, that would be 4320 rpm

note: 1. as u go up to speed, the top rpm will increase with speed

2. the example above will @ give best prop thrust figures if the engine power power peaks at 4800 rpm.

3. for low pitch @ 9 to 12 deg ( 1 click/notch? ) , use 0.95 x top running rpm


may not be exact but maybe this could give an idea......
 
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