Hi, I just picked up a green 73 Vette with the 454 and 4-speed. It's in great shape, but has manual steering and brakes. Is there any aftermarket solution for dropping in a power brake master cylinder? I have other musclecars that this is offered for, but dunno about C3 Vettes.

I think I am OK with the manual steering, but just in case, could that be converted over to power steering without too much drama? I doubt I will go down that road, since I like the precision of a good manual steering system over a power steering system, but just keeping my options open.

Also, how much horsepower does this engine realistically make?

Thanks in advance for any assistance.

Welcome to CF! :)
You can get an aftermarket rack and pinion steering.

Sweet. That way I could get a double upgrade. :D But I'll stick with the stock steering for now until I am sure I want to do that. :)

Here's one: http://www.vbandp.com/detail.aspx?ID=853
Here's stock: http://www.vbandp.com/detail.aspx?ID=989

I beleive power brakes were on option, on the small blocks at least. If you have room you should be able to switch it over, but don't know how much room you will have.

Welcome to the site. Any pictures? We love pictures. Don't forget the wave.

My '73 Factory Big Block came with power steering and brakes. The only clearance problems I know of might be the oil pan on the power steering and the drivers side valve cover. The valve cover needs to be concaved on the back outboard side to clear the power booster. I believe the booster is just a stock GM part. But you may need parts at the wheels. Cheers

Wow... a LS4 with manual steering and manual brakes. Did it come with a radio? Sounds to me like a car that was destined for the track. Do me a favor if you get the chance. If this is the original block for the car, a 3999289 block casting LS4, look above the oil filter on the drivers side of the motor. There you will find 3 capped off holes. I have been looking for other 4 bolt main 73 vettes with original LS4 motors. If it is a 4 bolt, there will be 2 large (1/2") plugs and 1 small (3/8) plug. If it is a 2 bolt all 3 will be the same size (3/8). Or... if you pull the pan... let me know what you see. I have an original 4 bolt in mine and allegedly only a few exist. Post your vin if you can... that would be great.
Thanks in advance for your time, and welcome to the forum. These guys are great and really know alot.
Later,
Wedge

Oh, and in response to the HP question, Chevy posted 275hp for the LS4 powered vettes. In 72 they changed the way they rated hp, from gross at the crank to rear wheel to get by the insurance industry and the EPA. It's compression was dropped slightly to 8.25 to run on unleaded fuel, and it lost a few ponies, but was still in the neighborhood of 360hp at the crank with 395 ft lbs of torque. Mine was crank dyno'd at 425, but with the taller hood to clear the intake, I don't see my right fender at all. A trade off I can live with! The sky is the limit... it is a great motor!
Wedge

ORIGINAL: blueshark

Welcome to the site. Any pictures? We love pictures. Don't forget the wave.

My '73 Factory Big Block came with power steering and brakes. The only clearance problems I know of might be the oil pan on the power steering and the drivers side valve cover. The valve cover needs to be concaved on the back outboard side to clear the power booster. I believe the booster is just a stock GM part. But you may need parts at the wheels. Cheers


Need to get some pics soon as I get a new digital camera this week. Mine won't charge any longer. :( Next one is going to be the kind that runs off of double-A batteries.

I see. I have made sheet metal aluminum valve covers before, so I might just do the same for this so I will have the proper clearance. I was considering just doing the PS conversion, and just running an aftermarket hydroboost, which would definitely spare a lot of room for the valve covers. I had such a system on my Satellite, so I guess I will see if the same is offered for the C3.

Thanks. :)

ORIGINAL: Wedge

Wow... a LS4 with manual steering and manual brakes. Did it come with a radio? Sounds to me like a car that was destined for the track. Do me a favor if you get the chance. If this is the original block for the car, a 3999289 block casting LS4, look above the oil filter on the drivers side of the motor. There you will find 3 capped off holes. I have been looking for other 4 bolt main 73 vettes with original LS4 motors. If it is a 4 bolt, there will be 2 large (1/2") plugs and 1 small (3/8) plug. If it is a 2 bolt all 3 will be the same size (3/8). Or... if you pull the pan... let me know what you see. I have an original 4 bolt in mine and allegedly only a few exist. Post your vin if you can... that would be great.
Thanks in advance for your time, and welcome to the forum. These guys are great and really know alot.
Later,
Wedge



I don't think it came with a radio, but there is an aftermarket one in there now lol. The funny thing is, I got a KILLER deal on it because nobody wanted it because it has no PS or PB. I figured, if I really wanted it, I could just get it.

I just checked, and mine has the 2 large plugs and the smaller one. What are those plugs for anyway? Some kind of provision for a dry sump system? I guess I will yank the pan sometime to be sure, but the 2 larger plugs are definitely half inchers. I know from having installed electric thermostats in my GTX. After doing that, I know how to tell the sizes. ;)

I thought my motor felt pretty powerful for a 70s big block, but I guess it just is powerful. :)

Thanks

You might be the only other LS4 owner I have talked to that has that plug configuration... and I've been at this since '97. They are for external coolers, sumps etc. But the best way to find out if it is a 4 bolt is to pull the pan.The answer I have been able to come up with is this: Chevy ran out of LS4 blocks for the 73 model year production cars. They pulled blocks destined for the racing program, which were milled for 4 bolt caps and external oilers. They were built to stock LS4 specs, just with 4 bolt caps.
Other 454 blocks for 73 came with 4 bolt caps, but they went into trucks, and some replacement blocks for that year had a CE suffix code. Look on the driver side of the block above the bell housing mount. If it is original the casting # will be 3999289. This block was used from 72-75, but only in 73-74 for corvettes. The date code is important and is located on the same spot on the opposite side of the block. It is in code, a letter and 3 numbers. The letter signifies month (A=Jan, B=Feb etc,) 1st number Date, last 2 year. Mine is K172 (Nov 1 1972). This will help you date the engine.
Is this a numbers matching car? You didn't say in your original post. That number is on the stamp pad in front of the passenger side head, that number should have a CWM suffix code (454/4spd), and correspond with your VIN number.
I don't mean to write a book here... but have you found the tank sticker on top of the gas tank, or did you get any original documentation for this car?
Let me know what you find out.
Later,
Wedge

I will definitely look for all of that in the AM. Yeah, it's a numbers matching car. I guess I got a better deal than I thought. The owner didn't know to much about Vettes, except that he couldn't sell it for the life of him, because nobody wanted an all-manual car with no AC. lol He hadn't done any internet advertising, just local paper. Maybe if he had, he would have realized what he had. I don't want to say what I paid, but even if it were a non-matching numbers mutt with a basic 2 bolt 454, I still paid a LOT less than I should have.

I'm turnin blue here! What have you found out... 2 bolt caps or 4???? The wait is killin' me... Let me know when you get the time...
Later
Wedge

If that baby is an original 454 car i would not modify anything and would keep it origianl. of course that is if it hasnt been heavily modified already.

Not sure if this applies to big blocks but four bolt small blocks used to have an eight inch harmonic balancer.

I got a question for you..... what motor is actually stronger??? a 2 bolt main or a 4 bolt main???

Def a 4 bolt. The journals are a lot stronger, allowing you to build to higher compression, and withstand higher revs and torque. I wouldn't trust a 2 bolt to hold together, when goin' over around 450 hp. Go 4 bolt, and you can really pump the sucka up without much fear of blowing the bottom right out of the block.

Dave pretty much hits the nail on the head. 'Nuff said!

hmmmm.... trick question:Dlet share with you why a two bolt main is stronger:eek:

uh-hum: A four bolt main is much weaker in the webbing area(where the main caps bolt in)due to GM drilling the outer holes too deep. You will get less core shift and main cap walking if you use splayed bolts on a two bolt main.

Sooo what is the strongest combo you ask??? a two bolt main converted to a four bolt with outer splayed bolts is the answer;), trust me on this one 2 bolt is good to 6800RPM and about 500HPwith some ARP bolts.

P.S. This is a tryed and true statement. time...and time....and time again

P.S./P.S. most people will not ever be able to use the HP an two bolt main can put out.

Street/Strip= two bolt main for up to 380HP@ 6000 RPM/nice ARP set up 500HP@6800RPMwith balance/SAFE!!!

DRAG ONLY= two bolt converted to a four bolt with outer splayed bolts and 'hardened' water jackets is a 'cheaper' 1000+HP bottom end for drag use.

"Sooo what is the strongest combo you ask??? a two bolt main converted to a four bolt with outer splayed bolts is the answer."

I had never heard this before. I have heard of drilling a 2 bolt to make a 4 bolt, but I had no idea of the effectiveness.
I was always told it was a "Bubba" thing. :D
Makes dang good sence to me, thanks for the great info. ;)

So,....does this apply to BB's too? :eek:

No it does not apply to CBB only CSB.
You can find these engine set-ups among the professionals quite often in 'under financed teams' but they will run like a scaulded ape with no drawbacks or problems, other than a dent in the wallet.:)

You are absolutely right about the 2 bolt conversion... it would be stronger. And Dave is right... 4 is a better platform for building high hp motors. If doublewasp's is an original 4 bolt like mine... it will be an extremely rare one like mine seems to be. I have been looking for 7 years now for others. I have been in touch with the NCRS judge for '73-74 Vettes, and he has been looking also. This was news to him when we first talked, and now after 5 years, he has not found another like mine. Doublewasp's sounded like a likely candidate because of the lack of options. His sounded like it was a COPO car ordered for drag racing. I sure hope he comes back to the forum... I would like to hear what he finds. And no matter what... I don't think I'll be posting this question on that 'other' site...

Hey Wedge, Theblock for my '73is a '73 4 bolt LS4 corvette block. It is not the original although the caris an originalLS4 454 4speed, I don't know if it had a 4 bolt or 2 bolt from the factory. The webbing is Identical to a 2 bolt block just with the bolts drilled at the factory. The blocks are the same with the exception of the mains and the oil cooler holes. It would be really easy to convert one and no one would be the wiser. So whats real and whats not?....go figure. The two bolts are pretty meaty in their own right. Take alot of abuse to granade it.

Yeah... good point. The castings were virtually the same. I have been told by one of the racing program directors (now retired) that because of the nature of the oil galleys cast in 4 bolts, they could not just be re-drilled or duped in a 2 bolt block. Even if it was done it would be a whole lot of work, and money for bragging rights that really don't matter... The 4 bolt galley configuration was for external sumps or oil coolers. Pro Team sez 2 or 4 bolt don't mean diddly, that Chevy did all sorts of strange stuff back then. At this point, I'm just looking to see if anyone else has one! Keep in mind that this isn't the only- after LS6 4 bolt block. Others were made for truck applications in those years, but they weren't LS4's, and the replacement LS4 3999389 that Chevy did offer had a suffix code of CE instead of CWM,CWR,CWT or CWS.
Oh, and BTW... I already voted for yours this month... good luck and hope you win!

So the internal oil passageways are bigger through out the block or just at the hole? If so that would mean completely different tooling. They didn't have lost foam back then. So one would have to look deeper internally at the three oil cooler holes to see if a block has been converted? I'll have to check fora suffix code on mine and see if it is an original or replacement if not converted. I checked mine against the numbers on a site(Don't remember the name) and according to them it was an LS4 block. In your search I'm sure you have come across a definitive list of numbers. Can you post them? I wonder how rare a replacement LS4 4 bolt block would be....any figures on that? I know the story that they only used the 4 bolts from the racing program because they ran out of production blocks, but if they were out of production 2 bolt blocks, where did the '73 replacement 2 or 4 bolt blocks come from?....Racing or the truck line I would imagine. Be kinda neat to find that out. Run across any info on that in you quest?

Thanks for the info. I love learning.

And thanks for voting. I never thought my C3would get more than one or two votes considering the competition. Cheers

The 4 bolt block LS4 was based on the 39633512 LS6 block. It was re-cast with the 3999389 LS4 casting number, but for all intents was a LS6 block. The 2 bolt block did indeed have different galley routing internally, and could be mimicked by re-tapping larger holes and drilling into the crank space, but it would not be the same as the original 4 bolt cast. As far as a definative list, the only LS4 is casting # 3999289. The suffix codes on the stamp pad used to match the vin number is what seperated them by option. CWS was California LS4/auto; CWT Cal. LS4/4spd; CWM 49 state LS4/4spd; CWR 49 state LS4/auto. I am not too sure about the castings of the CE block. I found out about them through Mortec (mortec.com) and the guy there wasn't in a giving mood... and I believe the date codes are later, cast in '73 and '74. My block was actually cast in '72 for the '73 production run. I posted the locations previously in this thread, along with how to decode a date stamp. Let me know what you find...
As far as numbers of replacemant CE code blocks... NFI (no ****** idea...) I don't think Chevy even knows that now. Their record keeping skills were and are for crap. The actual number of 4 bolts were somewhere around 250 (I heard) and they went into drag racing, the NASCAR program and even boats. Supposedly 12-16 were transferred to fill late production orders when they ran out of their stock of standard blocks. I was in contact with a guy who worked with some of the Baldwin Motion Vettes, and he was a treasure trove of info. I tried to reach him last year, but he passed away. He said "some" of the BM Vettes and Chevelles had 4 bolt blocks... but not all of them, and all were all COPO cars not off the lots. I wish I could get some info from the Yenko owners, but I think that program ended somewhere around '72. Any ideas on that?
Later... time for bed!
Wedge

What about the "low deck" VS "high deck"? :eek:
What exactly, are they?

Mortec, That's the site. according to them some casting numbers could be 2 or 4 bolts, if I remember right. I'll have to go out and take a look real close at mine. you've got me curious now. Cheers

Ps to the OP...Sorry if we hijacked the thread. It's just interesting stuff.

Finally got my pan yanked, and it most certainly is a 4-bolt. Pretty interesting. I like this car just a little more now. :D

One more question. What's the handling like between a big block Corvette and a small block? Does the extra heft really make things that much worse off?

Thanks

My only experience was with a '73 454. Compared to mine, it seemed to have a little more tendency to plow (undeersteer). Probably nothing that couldn't be fixed with some suspension mods. Both had stock suspension at the time.