How much HP out of this setup??

[Qaher]

hi all,, i just bought my 1st vette 1979 with the following mods on it:

can someone tell me how much HP I expect out of this engine setup:
-machined numbers-matching block—cylinders honed only so still 350in.
•Flat-top TRW pistons from Summit Racing
•World Products Sportsman II heads, 72cc chamber, assembled,
200cc intake runner, angle plugs. World Products #955-012150
Comp Cams Magnum 270H camshaft
Comp Cams Hydraulic lifters
•Comp Cams Timing set
•New timing cover
•Taylor plug wires with R&M looms
•New mini-starter from MotorCity Reman. .
•TCI Flexplate
•1800 Stall Torque converter
•High-Volume / High-Pressure oil pump
•Edelbrock Performer carburetor, model 1400 with calibration kit ( 600 CFM )
•Dynomax ceramic-coated headers with Percy's Dead-soft gas- kets and Stage 8 locking header bolts.
•Catalytic converter for exhaust system with Test pipe" fitted for carburetor tuning.

* New Bilstein shocks NIB ready to install
• New 700R-4 Transmission from Bowtie Overdrives with correct TV Cable for Edelbrock carburetor.
• New driveshaft (3 inches shorter than stock) necessitated by 700R-4.
• New Griffin Radiator with twin Spal fans (DeWitts)
• Both Trailing arms professionally restored by Bair's Corvette.
• Edelbrock Air/Fuel ratio LED meter in ashtray in center console—Bung welded into each header for tuning.
- K&N air filter cleaner model 1330.

any suggestion to get more power out of this setup? Thanx

 

[Peer81]

Depending on what quality fuel your running (Bahrein shouldn't be a problem for pure fuel for less money I think ). But you could try to bump the dynamic compression ratio up a bit. Don't know what your static and dynamic is right now but with that cam and no with no block decking you could make some nice improvement there. Depending on calculations zero deck?
Maybe flowing the heads?
Don't know what type of aircleaner you have, an open above the engine or a close getting cold above the radiator? Also don't know if the temp difference isn't that big in sunny Bahrain, but the colder the air more fuel can be added = more hp.

Groeten (greetings) Peter

 

[Qaher]

Depending on what quality fuel your running (Bahrein shouldn't be a problem for pure fuel for less money I think ). But you could try to bump the dynamic compression ratio up a bit. Don't know what your static and dynamic is right now but with that cam and no with no block decking you could make some nice improvement there. Depending on calculations zero deck?
Maybe flowing the heads?
Don't know what type of aircleaner you have, an open above the engine or a close getting cold above the radiator? Also don't know if the temp difference isn't that big in sunny Bahrain, but the colder the air more fuel can be added = more hp.

Groeten (greetings) Peter

K&N air cleaner pic is attached. what is needed to be done to get to 10.1 comp.? how much HP will i get with comp?I can make a vent on the hood so the filter face the vent and will get the cool air from out side the engine bay..what do you think of that idea? thanx

 

[73shark]

Welcome to the Corvette Action Center.

TRW 11 to 1 pistons (LT-1) should give you 10+ CR. The TRW catalog will give you the actual for your heads.

For cold air, an easy way would be to use a '73 hood since it had a cowl induction built in. Good luck w/ your mods.

 

[Qaher]

Welcome to the Corvette Action Center.

TRW 11 to 1 pistons (LT-1) should give you 10+ CR. The TRW catalog will give you the actual for your heads.

For cold air, an easy way would be to use a '73 hood since it had a cowl induction built in. Good luck w/ your mods.

thanx, i will keep that in mind,,, i am trying to gather as much info as i can so it will be easy for me to start moding it without any issues. i have to search for the 73 hood pic now..

 

[Peer81]

I think it's a good idea to first put your vette on a Dyno to see what you have now (HP) and go from there. CR is difficult to know if I don't know how deep the pistons lay in the block. I think the biggest thing is to look for cold air, so look for a 73 hood or maybe cheaper look for a dual scoop aircleaner like an 80 has, on a dyno its easy to see what the difference is. After that I would try to get the fuel air ratio as close as possible. And of course look what kind of a cat converter you have. Don't think an old one will flow that good (also mufflers?)..?

Groeten Peter

 

[Qaher]

ok,, my engine is a 355 with 5.7 L . can i make it 6.0 L ????

 

[Peer81]

A 383 isn't a big problem and with 72cc heads it should be possible I think. But first do some calculations to see where your static and dynamic go to. Would be ashame if you end up with an engine that only runs nice on race fuel
Google a bit on static compression explination and dynamic compression explination.
Or do what I also did, go to amazon.com and buy some books on the subject then you know it's a fact and not some 10 year old boy behind his keyboard on some forum.
Changing things without knowing what your doing is a very big gamble!

Groeten Peter

 

[Qaher]

A 383 isn't a big problem and with 72cc heads it should be possible I think. But first do some calculations to see where your static and dynamic go to. Would be ashame if you end up with an engine that only runs nice on race fuel
Google a bit on static compression explination and dynamic compression explination.
Or do what I also did, go to amazon.com and buy some books on the subject then you know it's a fact and not some 10 year old boy behind his keyboard on some forum.
Changing things without knowing what your doing is a very big gamble!

Groeten Peter

thanx peter for the valuable info. as you said i have to get it dyno first then we can take it from there. mostly i need torqui engine and not HP and i think a 355 engine is the right joice right?
thanx

 

[Vette79]

hi all,, i just bought my 1st vette 1979 with the following mods on it:

can someone tell me how much HP I expect out of this engine setup:
-machined numbers-matching block—cylinders honed only so still 350in.
•Flat-top TRW pistons from Summit Racing
•World Products Sportsman II heads, 72cc chamber, assembled,
200cc intake runner, angle plugs. World Products #955-012150
Comp Cams Magnum 270H camshaft
Comp Cams Hydraulic lifters
•Comp Cams Timing set
•New timing cover
•Taylor plug wires with R&M looms
•New mini-starter from MotorCity Reman. .
•TCI Flexplate
•1800 Stall Torque converter
•High-Volume / High-Pressure oil pump
•Edelbrock Performer carburetor, model 1400 with calibration kit ( 600 CFM )
•Dynomax ceramic-coated headers with Percy's Dead-soft gas- kets and Stage 8 locking header bolts.
•Catalytic converter for exhaust system with Test pipe" fitted for carburetor tuning.

* New Bilstein shocks NIB ready to install
• New 700R-4 Transmission from Bowtie Overdrives with correct TV Cable for Edelbrock carburetor.
• New driveshaft (3 inches shorter than stock) necessitated by 700R-4.
• New Griffin Radiator with twin Spal fans (DeWitts)
• Both Trailing arms professionally restored by Bair's Corvette.
• Edelbrock Air/Fuel ratio LED meter in ashtray in center console—Bung welded into each header for tuning.
- K&N air filter cleaner model 1330.

any suggestion to get more power out of this setup? Thanx

I'm a little skepticle of the cam choice. Cam may be to big for this setup. Need more data on the pistons. The only way to be sure would be to put it on the DYNO. We all could take guesses but we would prefer not to do that. You definitely are producing more HP then OEM. Many items that you had mentioned have no bearing on HP or TQ. Replace the stall converter if your looking for some noticeable TQ gains.

 

[Qaher]

how to find out about the piston size if i have no document about it? will the dyno be able to tell? according to this statement "cylinders honed only so still 350i" the pistons must be factory size but flat instead of dish maybe..!!!

thanx

 

[Rodney Gold]

You wont make the best of your available power , tho all your mods could , you need to get to about 10:1 cr , you prolly at 9 with the 72 cc head , 64cc is where you should be at for it all to work well. I am making close to 375 hp with almost your identical setup barring ally edelbrock ally performer heads and a 770 street demon carb , your 600 carb is a tad too small IMHO.
With a 2400 stall + 3.55 rear gears im doing mid to highish 12's on the stock BF tyres.

 

[Qaher]

You wont make the best of your available power , tho all your mods could , you need to get to about 10:1 cr , you prolly at 9 with the 72 cc head , 64cc is where you should be at for it all to work well. I am making close to 375 hp with almost your identical setup barring ally edelbrock ally performer heads and a 770 street demon carb , your 600 carb is a tad too small IMHO.
With a 2400 stall + 3.55 rear gears im doing mid to highish 12's on the stock BF tyres.

you are right , i used to have a 64cc that i sold brand new 2 years ago (AFR brand ). i thingk i have to get 750 carb and make my engine a 383. i am trying to keep my current parts and just play around it to save some money,, what best can i do?

thanx

 

[Peer81]

how to find out about the piston size if i have no document about it? will the dyno be able to tell? according to this statement "cylinders honed only so still 350i" the pistons must be factory size but flat instead of dish maybe..!!!

thanx

You could search the internet to find how much your piston are below the blockdeck. If I'm right standard is -0.25". The only problem is, to make a good calculation for CR and DR you need to know if you have a decked block or not or milled heads or not. The only way to find out is to take it apart (I think). Or you could take the gamble and think its all original.
If you want to go from a 350 to a 383 you'll have a bigger stroke so the 72cc heads could be your luck then, big change 64cc heads would be to small (to high CR)
Very simply said. your CR is all the air in the bore when the piston is down divided with all the air remaining in the bore with the piston all the way up.
Your DR is the same except this also takes in account your camshaft. When your piston is down your intake valve is still open so some air escapes when the piston goes up. DR begins to calculate the air when the piston is moving up when your intakevalve is closed (so the true air content so to say. The bigger the cam the longer the intake stays open so the lower your DR. CR is a good indication but DR is what counts. DR is max around 8.25:1.
If you want to calculate this, google on Dynamic compression ratio calculator and if you really have the time also look for download desktop dyno. With the desktop dyno you need to fill in a lote of info, but you can see what a cam change or changing from a 350 to 383 does to the engine. I don't see it as a spot on calculator for HP but its good to see what changes in the output

Groeten Peter

 

[Qaher]

You could search the internet to find how much your piston are below the blockdeck. If I'm right standard is -0.25". The only problem is, to make a good calculation for CR and DR you need to know if you have a decked block or not or milled heads or not. The only way to find out is to take it apart (I think). Or you could take the gamble and think its all original.
If you want to go from a 350 to a 383 you'll have a bigger stroke so the 72cc heads could be your luck then, big change 64cc heads would be to small (to high CR)
Very simply said. your CR is all the air in the bore when the piston is down divided with all the air remaining in the bore with the piston all the way up.
Your DR is the same except this also takes in account your camshaft. When your piston is down your intake valve is still open so some air escapes when the piston goes up. DR begins to calculate the air when the piston is moving up when your intakevalve is closed (so the true air content so to say. The bigger the cam the longer the intake stays open so the lower your DR. CR is a good indication but DR is what counts. DR is max around 8.25:1.
If you want to calculate this, google on Dynamic compression ratio calculator and if you really have the time also look for download desktop dyno. With the desktop dyno you need to fill in a lote of info, but you can see what a cam change or changing from a 350 to 383 does to the engine. I don't see it as a spot on calculator for HP but its good to see what changes in the output

Groeten Peter

thanx for the good info,,, so if i go 383 then i can keep the heads and the cam?? I know i will need to change the carb to 750 and don't know about the manifold intake!!!!

 

[Vette79]

You wont make the best of your available power , tho all your mods could , you need to get to about 10:1 cr , you prolly at 9 with the 72 cc head , 64cc is where you should be at for it all to work well. I am making close to 375 hp with almost your identical setup barring ally edelbrock ally performer heads and a 770 street demon carb , your 600 carb is a tad too small IMHO.
With a 2400 stall + 3.55 rear gears im doing mid to highish 12's on the stock BF tyres.

Rodney, your 2400 stall worked well for you? What type do you have? This is my next big purchase.

 

[Hib Halverson]

hi all,, i just bought my 1st vette 1979 with the following mods on it:

can someone tell me how much HP I expect out of this engine setup
(snip)

I'd say 350-360hp, however, the car's performance with that engine configuration is going to depend much on the car's axle ratio which wasn't listed.

any suggestion to get more power out of this setup? Thanx

If you mean a modest increase, I'd say you need proper tuning of the existing set-up and switching from that 600cfm Edelbrock to either a properly tuned Quadrajet or 750 vac. secondary Holley.

If you mean a lot more power, you need more displacement or higher rev limit, both of which will require spending a lot more money.

 

[Crimson Thunder]

Since you just got this Vette i would leave it alone and just enjoy it as it is for a while.After a couple of months i would look into making it faster(or quicker)I would start with a true set of dual exhaust and a set of 370 gears.

 

[Qaher]

Since you just got this Vette i would leave it alone and just enjoy it as it is for a while.After a couple of months i would look into making it faster(or quicker)I would start with a true set of dual exhaust and a set of 370 gears.

of course i will enjoy it first and at the same time i will be preparing the right setup. I am thinking of buying a used engine and build it to make it a 383. i will take my time building it while i am enjoying this one. every time i have some $$$ i will buy parts for the engine until it is ready for the swap.I am just trying to reduce cost and use the heads, the intake and the cam. I just the need the proper setup for building a nice power full engine for street and drag use (low 12's and high 11's will be great).i need to know a brand name for the stroker kit and the size of carb and whatever info that can help me build it right. I know about cars but don't know what is exactly required to reduce 450HP and I know it is different setup for drag only or street and drag or daily driving car.
thanx alot to all helping me here.

 

[Rodney Gold]

I would not go 383 , the cost vs the increased performance is not worth it - your 600 is ok for now , but it wont allow the max power , but will give you a bit better bottom end. Try putting the accel pump lever actuator in the top hole of the 3 on the edelbrock
Dont use ported vacuum for distributor advance and dial in about 36 degrees of TOTAL advance at 3500 rpm (disconnect vac advance) and then hook up vac advance to full manifold vacuum

As to the stall , it is a TCI , circle track stall, I stuck in 2 x tci 1900 rpm stalls and both grenaded within 100 miles.
The stall was the key to utilising my performance , the stock stall just chokes the engine.
The car launches violently from idle , goes sideway and can smoke the tyres , spins on the 1-2 shift too. I changed the diff ratio 1st , from 3.00 to a 3.55 and that had little effect , once I had the stall , it was night and day!!!!!!!
I was worried about daily driving with such a highish stall , but it is not a problem , the car still creeps at idle and it desnt feel like you are "slipping" , I can still tootle along at 1500-2500 rpm.
The fuel economy on my vette sucks , its about 3-4 km per litre when driving it in a "spritied" manner, so its about 15km per us gal or about 9-10 mpg. I dont worry about it as the car is merely my "toy"