Well, it's time to build a big motor. I've been running a procharged 489 for a couple years now and took it apart last month. Everything looked surprisingly good for 8k miles of street driving but I'd like to reassemble it as a 540. I'm gonna reuse my eagle 4.25 rotating assembly but go with a bowtie block # 25534362. I'm also going to reuse my AFR 305 heads and dart intake. Here is my question. I was running a Crane HR cam .610 .632 - 236/244 @.050 which was great on the street (and the car went high 10s with little effort). Should I be swapping to a bigger cam for the bigger motor? Maybe something in the 250 range? Keep in mind compression will be 8-8.5:1 and I will be running boost. I was thinking that a 540 with those heads and that cam would make insane torque even without boost. Also I may not reinstall the procharger in favor of twin turbos. The goal here is to have a very, very, streetable car that can go high 9s. What do you guys think. Some day I'll post a picture. This car is a wicked sleeper.:yes:

Yes, it is time for a MUCH bigger cam.

I'm in here b/c of the 588"er I wanna create one day along w/ another old junk301 just for the fun of it!!

Show those darn "ricer's" what SB and BB power is asll about................. He, He!!

pdq67

Well, you will have to decide if you want turbo's or procharger.
Cam specs are very different between the two.
I think you could achieve your goal very easily either way and you already have the procharger. But IMO twin turbos will be even more driveable. No whine and mellower exhaust. :)
I would get a cam ground based on your application.
And I would say yes, it's time for a bigger cam.
But it sure will be a nice streetable combo with killer midrange even with no boost.

What procharger were you running on the setup?

The procharger that I'm running is a D1sc. I know its a bit small for a 540. I originally bought it when I had a 396. The blower will support 925hp though.

Well, it's time to build a big motor. I've been running a procharged 489 for a couple years now and took it apart last month. Everything looked surprisingly good for 8k miles of street driving but I'd like to reassemble it as a 540. I'm gonna reuse my eagle 4.25 rotating assembly but go with a bowtie block # 25534362. I'm also going to reuse my AFR 305 heads and dart intake. Here is my question. I was running a Crane HR cam .610 .632 - 236/244 @.050 which was great on the street (and the car went high 10s with little effort). Should I be swapping to a bigger cam for the bigger motor? Maybe something in the 250 range? Keep in mind compression will be 8-8.5:1 and I will be running boost. I was thinking that a 540 with those heads and that cam would make insane torque even without boost. Also I may not reinstall the procharger in favor of twin turbos. The goal here is to have a very, very, streetable car that can go high 9s. What do you guys think. Some day I'll post a picture. This car is a wicked sleeper.:yes:

The bigger motor will run as a sleeper for sure with duration being at the 250's at 50 in duration. With dual turbos you will make insane power lower down in the RPM range. Being lower in the duration as well will suit your afr305's.
Go bigger on the lift and be sure to run at least in the 250's at 50. I would pick up on the lift as well.. Hope your car hooks.
just my 2cents.

I think that I'll limit lift to .632. According to AFR, the 305 heads are done flowing at that lift anyway. There is no sense in over working the valvetrain. How about pistons? I've always run JE, but lately, I've been hearing that Diamond pistons may be even better.

As far as the heads being done at .600 lift, they may not gain a bunch of flow above .600, but as long as they do not drop in flow, more lift can still make more power. You have to consider the time spent at higher flow. If you run more lift with the same duration, although the heads may not have picked up any flow at .700, the fact that the cam is opening the valve that far means that the heads will spend more time at higher lift where the flow is greater.

Adam

I ran a similiar 236/244 @ .050 in my 460. When I built my 540 last year I went with 264/270 @ .050 because of the added cubes. The motor runs great with this new cam.
I kept the lift down to .632 because I want the valve train to live on the street.
I feel .700 plus lift is too hard on equipment.
Yes I would go with a bigger cam but stick to 112 or 114 lobe centers.

Have had no issues on the street with .700 net lift, 262/270@.50, 114 ls, 335afr's solid rollered 540. Driven it on numerous 80 miles treks. Unbelievable drivability for that much power. Lotsa vacuum too. Mileage sucks.
And with some better 60"'s low 10 second quarters.
Big motors like big lifts, that's why I did it. Just hate to leave something on the table.
Touch wood.

My 540 has a set of 360 cc intake/brodix heads highly ported, a 871 blower, dual 850 double pumpers and a really tuned setup gets about 20 mpg on the open road.
I run 355 gearing and a .7 overdrive.
My air to fuel ratio's are in the 16 to 1 range under cruise. That is what gives the great gas mileage.
If you just fine tune the motor for maximum idle vacuum guaranteed you are running far far too rich at cruise. You can not just adjust the carb and expect it to really work for anything except WOT passes.
I spent and entire summer learning to tune, drilling and installing jets in the holley after buying a Wide Band oxygen sensor and 4 exhuast probes to learn what is really going on.
I doubled my gas mileage through my efforts and if called on the motor should put out about 1000 horse.

My 540 has a set of 360 cc intake/brodix heads highly ported, a 871 blower, dual 850 double pumpers and a really tuned setup gets about 20 mpg on the open road.
I run 355 gearing and a .7 overdrive.
My air to fuel ratio's are in the 16 to 1 range under cruise. That is what gives the great gas mileage.
If you just fine tune the motor for maximum idle vacuum guaranteed you are running far far too rich at cruise. You can not just adjust the carb and expect it to really work for anything except WOT passes.
I spent and entire summer learning to tune, drilling and installing jets in the holley after buying a Wide Band oxygen sensor and 4 exhuast probes to learn what is really going on.
I doubled my gas mileage through my efforts and if called on the motor should put out about 1000 horse.


That is shocking. :cool:
And probably the route to go for anyone contemplating running a high horsepower 540+ ci motor on the street. Even if you have money 5MPG gets tired real quick.

Thanks for the input, keep it coming. When I say I street drive this car I mean that I drive it every day. Between May and September I put about 4k miles on the car. I've been looking at a 254 / 262 at .680. from Crane. I think this is a step in the right direction but still small enough to have good manners.

That is shocking. :cool:
And probably the route to go for anyone contemplating running a high horsepower 540+ ci motor on the street. Even if you have money 5MPG gets tired real quick.

I have a small tank and if I want I can run 200 miles without thinking about gas. With the overdrive 2200 is 70 and 2500 is 80 so cruising on the open road is effortless. I run NO fans once on the open road. they are manually controlled and I turn everything off and the motor sits about 193 where I like it. If I want to play I turn on one and within a few miles I am at 180, turn on both fans and I cool down far too much.
I do NOT run a thermostat. I control the temperture with the fans.

Another advantage of the low compression with a blower is if I am going on a long trip I can fill up with the lowest of the lowtest and the motor runs fine. I can save 12 cents per liter of about 50 cents on the gallon and the low test actually gives slight better mileage to boot.
If I am going to lean on it I need the good stuff.
Do you run vacuum advance?? YOU need it to get better gas mileage, a cleaner idle and it doesn't hurt power if you are leaning into it.

Another advantage of the low compression with a blower is if I am going on a long trip I can fill up with the lowest of the lowtest and the motor runs fine. I can save 12 cents per liter of about 50 cents on the gallon and the low test actually gives slight better mileage to boot.
If I am going to lean on it I need the good stuff.
Do you run vacuum advance?? YOU need it to get better gas mileage, a cleaner idle and it doesn't hurt power if you are leaning into it.

I use a pro systems dominator. No vacuum advance. Idles really well, as Patrick at pro-systems said it would. I was surprised. :yes:
I need 94 octane at 35 degrees and race fuel added at 38 degrees with 11.5/1 compression.:)