I bought my '73 454 about 6 months ago and I will agree, there is no seat of the pants thrill regarding what I thought I would experience driving this car. My 2014 Chevy 4X4 and 2017 Acura RDX 6 cylinder will both eat up this 454.
My plan is to stroke my 454 to 496, swap heads, intake, cam, headers, go to 10.5 compression and I'm throwing around the idea of an EFI system.
I'm not a light to light driver and I want my performance running through the twisties on a long mountain or coastal roadway.
Where do you want your car to perform the best?
Look at what transmission and rear end gears you are running before you start ripping into your motor.
Could be you are running 3.08's when a 3.55 or 3.70 rear end gear will give you what you are after with the motor the way it is.

 

That dyno sheet was a .100 over 454 with a stock stroke of 4". That engine is a perfect fit for a C3.

 

Thanks for the replies guys. As far as tuning the car,yes the timing is set correctly and the carb as well. The tuner didn't mention a problem with the carb,but I guess that could be adding to my issues. I do have 3.70 gears already installed in the car too.

 

The car is a manual with air and power steering. I don't think they would have detuned mine as by 1972 the CR was already at 8.5 to 1

 

454 with stock heads before making any changes. Has roller rockers, Comp cam and headers


Spitfun- I just went thru this scenario with my 68 convert with a NOM 454 installed by the PO. Glad to see some of the forum members posting here who helped me out. I could not get any info from the PO on what had been done to the engine. Externally there were installed long tube headers, an aftermarket intake, and a 750cfm QFT 4 barrel carb. From the engine casting number, the engine was out of a 1978 one ton truck, rated at 250 hp at the crank. I took it to the dyno and got 304 hp at the rear wheels. When I started taking the engine apart I found roller rockers and a Compcam Extreme Energy hydraulic cam with 268/280 duration and .512/.520 lift. Pistons were flat top with about 8:1 CR. So- if you added a different cam and roller rockers to your car you could add about 50 hp.
I added aluminum heads, bigger cam, HEI ignition, upgraded fuel supply and got the dyno up to 336 rwhp. About $3k to gain 30 hp. The main holdup is the low compression ratio with the flat top pistons. However- the car revs quickly to 6K and feels fast, so I am going to leave it as is for now. I'd put a better cam and rockers in your car for less than $1k and see how it performs. I used a Lunati Voodoo cam with 273/279 duration and .542/.555 lift. It sounds really fierce under power and the rough idle keeps the Hondas and Toyotas hiding in the shadows. RA

 

Well....assuming the leak down test is good...(140 psi is pretty low but to be expected for the piston combo, however a "truck cam/rv cam" may boost that cranking pressure, its likely gonna drop when you put a cam in it but...all that being said, assuming the engine is very healthy, you can definitely wake it up.

First off, what is the casting number on the heads? We have no idea if they are decent early model oval ports or late model smogger peanut ports, so lets figure out what you have first. Honestly, I wouldn't spend money porting the heads, especially if they are peanut ports, I would just get rid of them all together. If you get some early-mid 70s 454 oval port/open chamber heads, they will not need any porting for what you want to do...Just a good valve job and some bowl work will go a long way. You can mill the heads some but...its not going to make THAT much difference in compression, it is worth doing it though if there is no plans for a piston swap.

Then come up with a cam that will wake it up but not be TOO big for the 8-1 compression.

Lastly, I would look at the intake/carb/air cleaner assembly and see what you can gain there.

At a minimum, I would expect a low compression 454 to make 250 rwhp with just about anything thrown in it, but I think doing some homework and careful part selection, you should be able to make an honest 300 rwhp.. I am just concerned why your power is so low now......


Its crazy when a stock 5.3l junk yard LS will make the same or more HP then a mild cammed 454...

 

You mentioned you have an aftermarket intake,may I ask what brand and model it is? I seem to be having a hard time finding an intake that will fit under the hood (I have the Big Block hood,not the L88 Hood). Thanks Rich

 

Weiand Stealth intake rect ports

I have a Weiand Stealth dual plane intake and a K&N 1 1/2 inch drop base for the air cleaner. Hood is a long style BB hood installed by the PO- not sure of the brand name- probably Chinese like everything else. The air cleaner has only the 2 inch high element, but when I did my dyno runs there was less than 3 hp difference between air cleaner on and off. I have about 3/8 inch clearance between the wing nut on the air cleaner and the hood. (Note the PO left the threaded rod on the carb really long, slammed the hood on it and spider cracked the fiberglass. I cut it to proper length when I removed his Chinese intake and installed the Weiand)

 

We always said "Money buys speed"

 

FYI, your hood is an aftermarket L88 hood. That intake and air cleaner assembly and measurments shown in your pics would never fit under a stock height BB hood.
Will

 

In my case it was $100 per HP to add 30 hp.

 

I dug up my dyno sheets from a few years back. My combo was a .030 over 454, slightly domed pistons (can't find the specs), a Summit 1302 cam with comp "high rev" lifters, edelbrock performer Q-jet RPM intake, 800cfm Q-jet, Stone stock 049 heads, 1 3/4 mid length headers. Compression was somewhere in the mid 9:1 range. It made 339 HP @ 5400 & 445 torque @ 3300. Through an automatic.

Since the dyno run I have swapped the heads for 781's fitted with 2.19 intake & 1.88 ex. The heads were milled and CC'ed. CC volume was verified at 114cc. I measured everything when it was apart and using a compression calculator the comp is 10.07:1 now. I'm using a .024", smaller bore cometic head gasket (Over the standard rebuilder type). I also swapped the headers for 1 7/8 full length with an X pipe exhaust. I have not dynoed it since, but my butt tells me it was worth a good 30 horse or so. It was enough to push my 4200 pound chevelle (with driver & gas) into the 12's. I would like to get back to the dyno this year.

As was posted earlier, You most likely have peanut port heads. Something isn't right, and this is through a manual trans? Pull a valve cover and google the casting numbers. I'm also wondering if the timing chain was installed off.

Here a few pics of my heads. The fresh ones are the 781's. 781 & 049 are basically the same head and an excellent head for street use. You really do need a domed piston to get any kind of compression, they have large chambers. I've seen on line anywhere from 112cc to 120cc. Mine measured 114 after milling.

 

There is a significant problem in your setup, for sure. Your dyno data shows the engine going 'flat' way too soon. Can't tell you what that might be: carb/cable/linkage not opening completely, timing 'good' per damper scale but not right for some reason, mismatch in head-to-intake or head-to-manifold orientation, ignition system issues.

Whatever it is, when you find the problem it will wake that engine up.

 

its the cams bullshit about what they will do after doing this and thAt to work as good as the stock one that was removed in the first place

 

http://it never ends

 

why did stock buick 455 put down such good stock horse power
with out all the big thinking tech guys
adding this changing that use to be find one put it in and drive the dam thing of coarse i drove a datsun picup with 500 caddy stock yup now drive a isuzu pickup with disappointed 454 sad *** crain cam a real waist of money should have left smog cam in ran a lot better don't buy the bullshit cam hype

 

I sure hope he has gotten it figured out by now, its only been two years ago.

 

Toobroke is that you again??

 

Two year old post, Joey....