I just got my 509 from Kahuner, he gave me a great deal and I am very happy with it!!
I was not able to track down the actual parts that were used to build the engine. He told me it was stroked with a forged SCAT crank. It has stock heads on it and a cam that goes up to 5200 RPM@450 Hp and max torque is at around 460.
What I am thinking about doing is putting on a set of Aluminum Performer RPM Oval port heads(110 CC), a RPM Air Gap intake, and a Performer RPM cam and lifters.
It will have the competition sidepipes for exhaust and a demon 750 for fuel.
I do not know what kind of pistons it has in it yet. I also do not know if it is a 2 bolt or a 4 bolt main block. The block has raised letters on the back that say "High Perf" It was decked so there are no serial numbers on the front tab.
The engine is going in my 81 street/strip vette with a turbo 400 w/2400 stall converter, and a 4 link rear with a yet undetermined ratio.
My Questions:
What pistons would I need for this engine setup?
What is the common bore and stroke to get 509 CI?
Is this a good combo (Performer RPM) for around 600 flyweel hp?
Is it likely that my block is a 4 bolt because of the words "High Perf" cast into the back of the block?
If it is a 2 bolt block, is it too weak for a 6500 rpm cam w/?600 hp?
What gear ratio would I want with this engine and a turbo 400 in a 81 Vette?
What timing gear drive would be recommend for this combination?
and,
Anyone have a part number for a nice oil pan that fits a bb in a 81 vette?
Re: Help me build my 509 for my 1981 - Please! (zZArAZz)
Quote:
I just got my 509 from Kahuner, he gave me a great deal and I am very happy with it!!
I was not able to track down the actual parts that were used to build the engine. He told me it was stroked with a forged SCAT crank. It has stock heads on it and a cam that goes up to 5200 RPM@450 Hp and max torque is at around 460.
What I am thinking about doing is putting on a set of Aluminum Performer RPM Oval port heads(110 CC), a RPM Air Gap intake, and a Performer RPM cam and lifters.
It will have the competition sidepipes for exhaust and a demon 750 for fuel.
I do not know what kind of pistons it has in it yet. I also do not know if it is a 2 bolt or a 4 bolt main block. The block has raised letters on the back that say "High Perf" It was decked so there are no serial numbers on the front tab.
The engine is going in my 81 street/strip vette with a turbo 400 w/2400 stall converter, and a 4 link rear with a yet undetermined ratio.
My Questions:
What pistons would I need for this engine setup?
What is the common bore and stroke to get 509 CI?
Is this a good combo (Performer RPM) for around 600 flyweel hp?
Is it likely that my block is a 4 bolt because of the words "High Perf" cast into the back of the block?
If it is a 2 bolt block, is it too weak for a 6500 rpm cam w/?600 hp?
What gear ratio would I want with this engine and a turbo 400 in a 81 Vette?
What timing gear drive would be recommend for this combination?
and,
Anyone have a part number for a nice oil pan that fits a bb in a 81 vette?
All help is MUCH appreciated!
:flag :chevy :seeya
You sure did get a good deal on that engine! If I were in driving distance, I would have bought it for his asking price.
All passenger car blocks say "hi perf" on the back, so that doesn't tell you anything. The heads usually say the same thing. The only way to check the mains externally is to look for the oil cooler line outlets near the oil filter. The 4-bolt usually, but not always, has the bigger outlets. You can probably find a few old threads here on the forum with pictures. A 2 bolt block is all you need for a street bb.
A "normal" 509 is built with a 4.5" bore, and a 4" stroke. Unfortunately, if your engine is really a GM "hi perf" block, it most likely doesn't have a 4.5" bore. 454s are built with a 4.25" bore, and cannot be bored to 4.5". If you have a "bowtie" GM racing block, it's possible. Check the casting number on the block (not the pad numbers).
Re: Help me build my 509 for my 1981 - Please! (zZArAZz)
I owned a 509 which is still racing today in a friends 67 camero. It's made by doing the max .120 over bore of a 454 chevy and installing a 4.25 stroker crank So the bore is @4.370.
The only bad thing about them is that's it for the block. It can't be bored any bigger so when it wares out you toss it.
Since your going for aluminum heads I would shoot for high 10:1 C/R When you pull your heads just see if your pistons are dished and how many cc. I use http://www.smokemup.com for my calculations.
Your building an animal motor so don't think in terms of small intake port and a dual plane intake for low end torque. Your going to have all you need with 509 ci. So just get some really high flowing heads and a single plane.
I'm pro solid roller cams, But solid flat would also be a good choice.
You could try and run the 750 speed demon, but your motor is going to starving for air. The basic rule is 1.6 cfm per hp so your 600X1.6=960 cfm.
I don't like or use gear driven cams. If you want the blower sound - go buy a blower. I use all Crane cams components. So I have the billit roller chain drive.
I have a Morroso 8 quart road racing pan and it didn't fit on my 79 Vette. It smashed into the steering arm. The fix is to space the steer down 1/2 inch on the drivers side where the 4 bolts attach to the frame.
For the gear ratio you need to determine if you want max 1/4 mile time and speed or lowest highway rpm. with 600 hp you would be going somewhere around 130 mph in the quarter. So something like 3.90 gearing with 28 inch tall slicks would put you through the lights at just over 6000 rpm
Re: Help me build my 509 for my 1981 - Please! (gkull)
I was hoping to stay around the 600 hp range so I would not tear my car to pieces:)
I liked the Edelbrock RPM Aluminum heads because they had the slightly smaller combustion chambers (110 cc) and I thought it would bring my compression up just enough to be able to keep my current pistons.
I was figuring a 340 cc intake square port head setup with roller would be in the 700+ hp area and be just too much for me..
Edelbrock claims on their site that a 9:1 454 makes over 540 hp with the rpm heads, cam and air gap manifold. I estimated with my 509 ci, super comp side pipes and a ram air scoop I should hit my 600 hp goal.
RPM has both Oval and Square port heads with the matching intake manifolds. Can someone explain what the advantages are for either setup?
GK please list alternative parts that you would reccomend to hit the same hp goal?
Thanks!!!!
:flag :chevy :seeya
Re: Help me build my 509 for my 1981 - Please! (zZArAZz)
I don't think that people realize that 50 additional cubic inches doesn't make much additional HP with all other components being the same. Your TQ will go up.
So a 454 with a certian head flow CFM and a cam that makes 540 hp will still only make 540 in a 509 ci because the air flow didn't change.
A power rule of thumb is: The more head cfm of flow the less radical of cam you need to produce the same amount of power.
Re: Help me build my 509 for my 1981 - Please! (gkull)
Gkull: I am just worried about added costs and problems with trying to match up high flowing heads with lower rpm powerbands.. I am assuming my block is a 2 bolt main, and I would like to stay under 6500 RPM. However if I throw on some high end large valve, large flow heads, I will have to worry about spring sizes to match up to a smaller cam, and I would probably have to change my pistons to match my cams compression needs. The matching cams for the high flow heads start at 3800 rpms! way out of my league with my current setup. The combustion chambers on the RPM heads are 110cc. I beleived that would raise my compression up to between 9-10:1 The RPM assembled heads have matching intake and cam so everything is set to work together properly for a lower rpm range engine.
Well for around $150 more each then the RPM heads, I found these:
And that leaves me stuck on what camshaft to use. All these parts are designed to run 3500 - 7000+ RPM range, and are not very street friendly.
Change out springs and pistons, and run a solid lifter setup or a Hydraulic Roller?
How about the brodix heads, with a RPM cam and square port Air Gap intake?
Could that engine combination work good with a 8.5:1 compression ratio?
Do you think I could match up parts to work with the Brodix heads and a rpm cam profile?
Thanks again for your help!!
Re: Help me build my 509 for my 1981 - Please! (zZArAZz)
I spoke with Kahuner a good bit when he was getting that engine together. We worked a lot on defining exactly what he intended to do with it and how he wanted it to act. I probably drove him nuts with questions about his wants and what parts were actually going into the engine. It's been a while, but I'm pretty sure it's 454 block with a 4.250 crank. Not really sure what bore he settled on, but it was somewhere between .100-.125. If he says it's a 509 , he must have used the .120 that GKull listed. There were a lot of variations being bounced around during it's planning because the builder was a buddy of his and had access to just about any crank, block combo you could come up with.
He wasn't going racing,but basically wanted the power of a 427/425 motor in a pump gas version with zero maintenance. He was also planning to use stock manifolds and side pipes at first and that had a big impact on things. He wanted it to get sideways in second gear if he wanted it to, but really had no intentions of revving over 4500-5000 rpm. He wanted it to lope a little, but not shake the car to death or cause lots of carb tuning problems. Basically a low RPM torque monster with most of it at the very bottom end.
The cam we chose (and I believe he actually used) was a Comp hyd flat tappet. It was 234/244@.050, .564/.570 on 111 LSA. We looked at a 226/234@.050 one but I think he went with the larger one. He's bound to have some info around somewhere.
But on to what your plans are now. The combo you listed is way mismatched, Those are great heads, but not on your motor. I have them on my 540 and most folks consider them too big. But trust me, I love them. But I have a pretty aggressive cam and valvetrain and a Dominator on it to feed it. Plus I don't mind running it pretty hard.
You definitely don't put a dual plane anything on heads like that. It will kill it. You have a long stroke motor there that will never have a problem making more low end than you need. I've seen several 496 motors make 650-660 hp with flat tappet cams and Merlin oval ports. I have a friend with a 502 (4.470x4.00 stroke) that makes 610 hp with well ported GM Iron oval ports and a hyd. roller cam on pump gas.
The RPM cam would be terrible with those heads. You can use a relatively small cam with good heads, but that is too much. The -2 or -2x heads would be better for you than the 2Xtras. The GM or Edelbrock rectangular ports would be good choice for you. I would shoot for compression to be at LEAST 10.5 with aluminum heads. No problem on pump gas. No way is 8.5 good for anything unless you have a blower on top of it. There are some 100cc Edelbrocks out there too marketed as High Torque or something like that that might help you achieve decent compression with your pistons.
You really need to give us a lot more specifics to help you with cam, intake and head choices.
What gears and trans will you end up running?
What accessories does car have?
How much highway driving?
How much in town driving?
How many mies per year?
Weekend warrior or really a car that gets driven on long trips etc.
Do you plan to race it in any form, or mainly just stoplight running etc?
How much do you like to work on it?
Try to find out what pistons he actually used. I'm thinking they might have been some Hypereutectics.
What head castings are on it now?
You can easily run deep 11's with GM Iron heads and a little work. Big race heads aren't necessary or even desirable unless you need them.
If you really decide to go with aluminum ones, I know of a couple of Forum folks that are thinking of upgrading from their present ones. You might be able to score a heck of a deal on a set of heads they have "outgrown".
Re: Help me build my 509 for my 1981 - Please! (427Hotrod)
Hi 427HotRod,
I want drive the car on the street but I want it set up for a 1/4 mile with somewhere around 600 Hp. I would like to keep the 509 short block together, I was hoping to only have to buy these parts to reach my goal:
Oil Pan, Timing chain Cover, timing chain, cam, lifters, aluminum heads, intake, and Carb. I recently purchased a 400 Turbo and a 2400+ Converter.
I am planning on purchasing a 4 link setup for the rear and wanted to gear it according to the engine parts. The car will be setup with power steering. I have a 200 amp alternator to power the stereo etc... The car came with Air, but the compressor and lines have been removed.
Mabye 6000 Miles of friday night cruising per year. No highway driving...
I plan to take it to National Trails Dragway occasionally which is about 15 mins from my house.
I have not really touched the car in years, but my brother recently built a Buick with a 502 so he has shamed me into getting rid of my smallblock so I can compete:)
I am picking up a engine stand in a few days and I will get a better idea of what parts I am dealing with.
I did want to go with new aluminum heads..
Also I would like a rough idle, but not too rough:)
I am ready to order these engine parts from Jegs asap since they are right next door to me..
Thanks for all the info , and for your help!
-Max,
614-778-9399
Corvette Store
Help me build my 509 for my 1981 - Please!
