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Topic Review (Newest First)
06-02-2008 09:41 PM
DENCOUCH
Thanks guys

I honestly appreciate all of the great help with this build. If you examine my track record, I have not the excellence nor knowledge nor experience to make this a success on my own.

You men are doing a great service to everyone in need of honest, well thought out help. I can't thank you enough.
06-02-2008 06:13 PM
machine shop tom
Quote:
Originally Posted by F-BIRD'88
1. This is a dyno and on the street real deal proven combination........
Keep it simple.
I agree with almost all of that. The only thing I wouldn't recommend is millng quite so much off the heads. You would be horsepower and reliability ahead if you straighten the decks enough to improve the quench. I'd be leery of using a steel shim head gasket without machining both mating surfaces. This is based on 25 yrs. of seeing what can happen when that isn't done. By taking some off the heads and deck you are accomplishing both improving quench and ensuring good gasket sealing, along with increasing the compression ratio.

BTW, I'm not a big fan of steel shim gaskets.

tom
06-02-2008 05:11 PM
F-BIRD'88
Quote:
Originally Posted by Double_v23
I have scanned through this thread, and I may have missed some things but here is what I would suggest.

Ditch the lift rule cam...it will kill a street car and you will end up spending more on drivetrain to compensate for the duration. (gears, converter etc)

Check out beehive (conical) valvesprings from crane, these will allow you to run alot of lift at the same installed height as the stock vortec springs. WITHOUT MACHINING.

If you are going to rebuild the bottom end, get a better piston than those 345's something with a flat top and two valve reliefs. There are some really reasonable forged pieces out there that are well worth the extra coin. You just need to know what you are looking for specifically because these are not always advertised widely in the popular shopping spots.

Get rid of the steel shim idea...GM makes a gasket (10105117) that is a composite and is only .021 compressed thickness. (they advertise it as .028 but I have checked them myself) This will eliminate the common problems with steel shim head gaskets and only give up .006 quench.

Like CNC said, you will not be happy with your "budget" motor unless you put a little extra cash into the places that count. And if it takes a few hundred bucks extra to be able to run whatever cam or compression ratio you want then you should go for it, otherwise you will probably be doing it later.

1. This is a dyno and on the street real deal proven combination.
It makes the power I say it does. (410 hp with a lowly performer manifold)
it will make 10 to 15 more with a performer RPM hi rise.
It makes in excess of 400Ft lbs with a near flat usable torque curve with just 9.5:1 compression.

It kicks *** on the street. This motor is all about torque. We installed two version of this motor in two different cars and the on street performance was very impressive.
The idle sound is very cool.
If you assemble it exactly the way i outlined, you will get the results I say you will.
No machining is required other than shaving the heads to 58cc in your case.

You do not need to spend a fortune to do it as discribed. it works and is dependable.

2. I've never had a steel shim head gasket fail on me yet. Even at 12.65:1 compression.

3. Both the customers that these motors were built for are still very happy. Both motors were built with lowly cast pistons and are still in service today. 1 even has a 125hp nitrous kit on it. They have nothing more than what is in your GM crate motor short block right now. If you can break it, you're a better man than I.

Don;t need any $$$$beehive springs, forged this, roller this roller that, decking, bore C/L correcting, $$$$ etc etc.
Just put it together and go. Change the oil and filter 3 or 4 times a year and other wise leave the hood closed and enjoy.

You will want a high stall torque converter and some gear and will want to recurve the distributor. nothing more than you would do for any other 350ci build of this power output.
Keep it simple.
06-02-2008 01:43 PM
machine shop tom
Quote:
Originally Posted by F-BIRD'88
So the catalog is correct. My motor was built with these pistons well over 10 years ago.
Looks like the spec on the recent hyper H345NP pistons has changed.
Do yours have the coated skirts? Mine did not. Had to replace one to repair that motor. Thats why I had to measure mine.
Thanks for the update Tom
They are coated, hence the "C" in the H345NCP (and other SP piston part #s).

tom
06-02-2008 12:59 PM
F-BIRD'88
Quote:
Originally Posted by machine shop tom
I measured the H345NCP. It has a 1.560" compression height. The same as what I measured on some a few years ago. Which I forgot.

tom
So the catalog is correct. My motor was built with these pistons well over 10 years ago.
Looks like the spec on the recent hyper H345NP pistons has changed.
Do yours have the coated skirts? Mine did not. Had to replace one to repair that motor. Thats why I had to measure mine.
Thanks for the update Tom
06-02-2008 12:33 PM
machine shop tom
Quote:
Originally Posted by ap72
Am I the only one who goes to "zero deck height" when I bother to get it decked? If you just go to 9.00" thne you can use whatever gasket you want to gt your desired quench... also the super thin gaskets tend to have more problems... not that there's a lot, but there is more.
I just like to leave a little wiggle room for next time.......




tom
06-02-2008 11:59 AM
ap72 Am I the only one who goes to "zero deck height" when I bother to get it decked? If you just go to 9.00" thne you can use whatever gasket you want to gt your desired quench... also the super thin gaskets tend to have more problems... not that there's a lot, but there is more.
06-02-2008 09:47 AM
machine shop tom 'I would like a truck built around a 350 sbc. When I step on the gas, I would like it to go as fast or faster than traffic. mileage is not an issue with me. I am willing to give up some bottom end torque for some scoot. My plans are to address the rear end with 3.73 or 4.11 gears, coupled to a stall converter with around a 2600-3000 stall to work with the cam that was recommended."

This build need not have forged pistons or any other more expensive parts. Good gaskets, bearings and moly rings will compliment the build to achieve what the target goals are.

Personally, as far as deck height is concerned, I'd deck it to 9.010" and use a .035" composition gasket to get .045" quench. That would be fine and not raise the CR any more than necessary. I would watch the total timing carefully so as not to contribute to detonation.

tom
06-02-2008 09:06 AM
Double_v23 I have scanned through this thread, and I may have missed some things but here is what I would suggest.

Ditch the lift rule cam...it will kill a street car and you will end up spending more on drivetrain to compensate for the duration. (gears, converter etc)

Check out beehive (conical) valvesprings from crane, these will allow you to run alot of lift at the same installed height as the stock vortec springs. WITHOUT MACHINING.

If you are going to rebuild the bottom end, get a better piston than those 345's something with a flat top and two valve reliefs. There are some really reasonable forged pieces out there that are well worth the extra coin. You just need to know what you are looking for specifically because these are not always advertised widely in the popular shopping spots.

Get rid of the steel shim idea...GM makes a gasket (10105117) that is a composite and is only .021 compressed thickness. (they advertise it as .028 but I have checked them myself) This will eliminate the common problems with steel shim head gaskets and only give up .006 quench.

Like CNC said, you will not be happy with your "budget" motor unless you put a little extra cash into the places that count. And if it takes a few hundred bucks extra to be able to run whatever cam or compression ratio you want then you should go for it, otherwise you will probably be doing it later.
06-02-2008 07:55 AM
DENCOUCH
Thanks MSTom

Thanks or your efforts. Now, before I part with any greenbacks, allow me a second to see if I am clear on this.

Utilizing flat top pistons will give me a better shot at controlling quench than using dish pistons, true?

I can add the measured piston height to the head gasket thickness to determine if my quench is tight enough?

If quench is tight enough, then I will not build myself into a corner where I cannot run this motor on pump gas?

Thanks for the enlightenment!
06-02-2008 07:35 AM
machine shop tom I measured the H345NCP. It has a 1.560" compression height. The same as what I measured on some a few years ago. Which I forgot.

tom
06-01-2008 09:08 PM
DENCOUCH
Thanks for the info.

Thanks guys for your help. I haven't ordered pistons as of yet, so I am unencumbered at this end. No bridges burned here.
06-01-2008 06:44 PM
machine shop tom
Quote:
Originally Posted by F-BIRD'88
Cannot guarante that the hyper H345NP piston will have a 1.56" pin height.
The F-M book specs are 1.54" for the plane cast 345 piston and 1.56" for the hyper version. (I'm of the opinion this is a typo based on my past H345NP piston measurments.)

My old 350 had the hyper "H345np-60" pistons and had a 1.54" measured pin height. I measured myself when we tore the motor down for repair.
My block was decked a lot lot. Piston was .018" down the bore at TDC.
I have a set in the shop I'll measure tomorrow (if I remember). Somebody PM tomorrow morning (so I don't forget).

tom
06-01-2008 05:33 PM
F-BIRD'88 Cannot guarante that the hyper H345NP piston will have a 1.56" pin height.
The F-M book specs are 1.54" for the plane cast 345 piston and 1.56" for the hyper version. (I'm of the opinion this is a typo based on my past H345NP piston measurments.)

My old 350 had the hyper "H345np-60" pistons and had a 1.54" measured pin height. I measured myself when we tore the motor down for repair.
My block was decked a lot lot. Piston was .018" down the bore at TDC.
06-01-2008 05:18 PM
DENCOUCH
F-bird-88

Thank you for cutting me some slack on my mis-measuring. Yes, I am a dolt!
I honestly did write down .090 as the piston to deck measurements only to screw it up with my fancy Photoshopping.

The 10 inch stall converter sounds great, It will be on the list!

The Vortec heads are staying stock with the exception of your spring suggestion. Everything is going to work around the "Lift Rule" Isky cam you suggested. I want to shave the heads a bit not only for the sake of decreased chamber volume, but to insure a flat making surface for the .015 steel shim head gasket.

I have short tires,but wi-i-i-de! The truck is dropped 4", and she probably weighs 4000lbs.

I am one of those lucky guys that live only 10 blocks from work. I drive exactly 1 mile one way. I have another car at my disposal if need be (Translation: Gas goes to $10. a gallon), so gas is no problem with me.

I am ordering flat top pistons with a Compression dist of 1.560 and a Deck Clearance of .025. I am hoping to engineer a quelch of between .030 & .040.

So good so far?

Thanks for you help and guidance. You don't know how much it is appreciated.
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