new purchase question

[davidl13]

i am looking to purchase a b body with a 73' 440 block with 452 heads...all stock rebuild except msd ignition... what kind of performance can i expect with this setup... and do you have any recommendations...

it will be used as a daily driver, reliability is most important, pump gas, and performance...decent gas mileage if possible... in that order

thanks in advance for your help....

 

[Meep-Meep]

I'd say high 14's to mid 15's at 95 MPH or so. More compression (9.0:1), slightly more cam and headers with low restriction duals will make a huge difference. Nothing lower than 3.23 gears.

 

[davidl13]

i forgot it has a purple cam and 3.23 gears....

are the 452 heads good ones, i really don't know anything about the different blocks and heads... any info and help is greatly appreciated

 

[Meep-Meep]

So much for the stock rebuild!

Purple Shaft cams come in many flavors so you need to know which one you have. Assuming you have the low compression 73 pistons chances are you don't have enough squeeze to make that cam work. Yank it out and get something that is designed for low compression. Shoot for 160 PSI cranking pressure for reg 87 R+M/2 gas.

I don't think 452 heads are anything to rave about but good results can be had if they are prepped correctly. The hard seats are a plus. Big valves and pocket porting is helpful but you will loose the factory hard seats - and head work gets pricey. My factory head choices are closed chamber 915's followed by 906's.

 

[69 Runner]

Yup, what he said. Most all of the M.P. cams are "purple". There is no grind that is identified as "purple"

 

[davidl13]

cam

ok, thanks for the help guys...

here is more info

the cam is 284/284.....484/.484 lift, part #312-p4120232

the block is the bottom one with the figure 8 style water guides

[/IMG]

 

[Meep-Meep]

I believe that's a motor home block. No issues with that that I can think of. Do a cranking compression test and get back to us with the numbers. The .484" cam can be the kiss of death.

 

[davidl13]

ok, did a compression test and came up with 101-107 on all cylinders

 

[Satellite65]

You'd be lucky if your CR is 8:1 with those cranking compression #s. Be very mindful of your cam selection as you will kill whatever little bit of low rpm torque you have if you go too big. Shoot for a cam with low overlap and an early intake valve closing point to keep the cylinder pressures up.

Other than that, change your pistons to raise the CR.

 

[davidl13]

what compression can i have and still use pump gas and remain reliable...

i dont really understand your guidlines on the cam selection or how to optimize an engine build... i could use some more detailed help on how and what to do to this engine to make it a great, street, every day driver, highly reliable, with enough power to at least out do my dodge magnum rt (5.7l hemi) and hopefully best a lx bod srt8...

thank you for all you help

 

[Meep-Meep]

Those compression numbers are great - for an air cooled VW! You can do a cam change and save your engine. Look for something specifically designed for around 8-8.5:1 CR. I think Edelbrock makes a good cam for that application. Your target cylinder pressure should be 160 PSI for regular gas and a stock intake and carb will be fine. If you want more power you will have to change your pistons and put a slightly bigger cam.

As far as what compression you can get away with depends on a lot of factors, but I can tell you for sure that 190 PSI and 10:1 will not work with 91 R+M/2 on a hot day.

 

[69clone]

those 400 blocks are pretty sweet and can make some power, From what i've read the biggest problem is low CR, Fixing that will be the best thing to do. not sure what year b body you have but i want to put a 400/512stroker one in my 69' They look almost identical to a 383, If you want to replace the pistons,etc and want some power you should check out the strokers on 440source.com under 2grand you can have everything to gain 51-112 more cubes out of that block. But if you want the stock displacement getting the CR up is your biggest thing. As far as how high you can go, I've heard people claim to have 11.1 that run pump gas.

 

[davidl13]

i live in south florida, so for half the year, i have 85-95 degrees and humid, so what i build needs to tolerate pump gas in hot weather

 

[davidl13]

ok, faulty compression tester... actual results are 121-126

452 heads

the cam is 284/284.....484/.484 lift, part #312-p4120232

holly 750 dp

 

[Cranky]

What you want is a cam that's similar to an RV type cam. They raise the cylinder pressure thus making a low compression engine think it has more as it runs but the intake valve doesn't close early...it actually closes a bit late. It opens late too which creates a lot of vacuum. The intake begins to open as late as 0 TDC and as the piston gets near the bottom on the intake stroke, and is about to come to a stop just before it starts back up on the compression stroke, the air/fuel mix is still rushing in packing the cylinder full. That said, you can also advance that 284/484 5 or 6 degrees and it will do a good job making that low compression engine run better on the low end. Of course, you'll need to use a degree wheel to make sure you get it set where it needs to be. There's lot's of sites that show how it's done but http://www.carcraft.com/howto/116_0701_how_to_degree_a_camshaft/index.html is one of them. Comp cams and I hear Mopar Performance cams are ground on a 4 degree advance but I still move them up some for a streeter. Comp says their cams are precision ground and don't need to be degreed in....I say BS to that. There's also a lot of info on the net about how cams work and what all the different numbers mean and do but unless you plan on becoming a cam expert, it's a waste of time. Are you good and confused yet? lol

 

[Meep-Meep]

ok, faulty compression tester... actual results are 121-126

452 heads

the cam is 284/284.....484/.484 lift, part #312-p4120232

holly 750 dp

Still not very good. Get rid of that cam and put in something that has an earlier intake closing spec (I.E. smaller). I'm running the MoPar .455" lift cam in a 440 and pulling a 3700 lb B body through the traps at 109 MPH on street tires. You don't need a huge cam to make good power.