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-   -   Horsepower estimate for the Gen III Vortec V8 (http://www.hotrodders.com/forum/horsepower-estimate-gen-iii-vortec-v8-227866.html)

Rmatt87 01-02-2013 04:51 PM

Horsepower estimate for the Gen III Vortec V8
 
Hey HotRodders,
I was on here earlier looking up how to build the cheap made in mexico 350 V8 and seen how big the gain in horsepower was with the ported Vortec heads, intake, and Holley carb. I realized that i have a Vortec engine thats in great shape so ive decided to build this block for my S10 V8 conversion. I was wanting to know if anyone can give me an estimate in horsepower if i use a Big Mutha Thumpr Cam from COMP Cams, ported Vortec heads, big long tube headers, Flowmaster 44 mufflers, Edelbrock Performer RPM intake manifold (Dual-plane, High rise), and a 750 CFM Edelbrock Performer Carb (calibrated for performance). The camshaft has an RPM range of 2600 to 6800 and the valve lash is listed below:

Intake Exhaust

Duration 291 311

Duration@.050" Lift 235 249

Valve Lift 0.573 0.558

Lobe Lift 0.338 0.329


I will be using the recommended kit from COMP Cams and the compression ratio recommendation of 9.5:1. I haven't decided on the type of ignition system as far as the distributor goes so if anyone has any suggestions that may work with this application feel free to let me know. I apologize for writing so much for the first time.

Matt

hcompton 01-02-2013 06:06 PM

Quote:

Originally Posted by Rmatt87 (Post 1629855)
Hey HotRodders,
I was on here earlier looking up how to build the cheap made in mexico 350 V8 and seen how big the gain in horsepower was with the ported Vortec heads, intake, and Holley carb. I realized that i have a Vortec engine thats in great shape so ive decided to build this block for my S10 V8 conversion. I was wanting to know if anyone can give me an estimate in horsepower if i use a Big Mutha Thumpr Cam from COMP Cams, ported Vortec heads, big long tube headers, Flowmaster 44 mufflers, Edelbrock Performer RPM intake manifold (Dual-plane, High rise), and a 750 CFM Edelbrock Performer Carb (calibrated for performance). The camshaft has an RPM range of 2600 to 6800 and the valve lash is listed below:

Intake Exhaust

Duration 291 311

Duration@.050" Lift 235 249

Valve Lift 0.573 0.558

Lobe Lift 0.338 0.329


I will be using the recommended kit from COMP Cams and the compression ratio recommendation of 9.5:1. I haven't decided on the type of ignition system as far as the distributor goes so if anyone has any suggestions that may work with this application feel free to let me know. I apologize for writing so much for the first time.

Matt

What year v8 is it you mean genII? I think gen III is LS motor.

Also note it says atleast 9.5:1 you may want to hit a little more cr with that cam. You may also want to think about the smaller one unless you are going for some big power. Have you checked the drc with the bmt. Ots very low with less than 11:1 compression. Intake closes at 71 degrees @ .06" so its a big cam and will act like one. Not that i am agaist it got one my self going into my next build but i am realizing its going to have a dcr in the low 7:1 area. So i had to make some changes in my build to hit a much higher compression number. It will surely run at 9.5:1 but if you want it to really pop off you may need some more cr.

What type of heads are you running. Bmt is a big breather crappy heads even ported will not flow enough. Unless you have the good vortech castings you may not get the results you want. Cam is peaky if heads are low rpm they will miss each other. If your going to run the bmt you at least want the big end punch. I think there is only one vortec head that is any good comes in two casting numbers 906 i am not sure of the other. There is also a bowtie head that is very good.

Rmatt87 01-02-2013 06:26 PM

It is a Gen III LS1 engine i believe. It was in a 1997 Chevrolet Silverado 2500 4x4. The casting numbers for this block is 14093638. After i google the casting number on the back of the block it says its a 5.7L Vortec. The heads have a 64cc chamber. The valves are 1.94/1.50 but heads are machined to accept 2.02/1.60 valves. Not sure what that means. The 9.5:1 compression is their recommendation. I thought about bumping it to 12.5:1 CR. I already have the pistons if i do the higher compression. Again im not sure if i even want that high of compression. Thanks for your response.

vinniekq2 01-02-2013 06:32 PM

drop that LS engine in the car as it came from the factory.After you convert to carb you should stop moving backwards

Rmatt87 01-02-2013 06:52 PM

UPDATE!!! After a quick research ive learned that i have the 64cc TBI heads. Shouldve known since the engine is a TBI. I didnt get to look for the casting number BUT by the casting marks on the outside of the head i see the double bar. www.crankshaftcoalation.com says the casting num. is 193 and even has pics. This head is not recommended for high RPM performance unless serious port work is done. Anyone know what kind of port work would need to be done to make these work?

Rmatt87 01-02-2013 06:54 PM

vinniekq2- moving backwards??

vinniekq2 01-02-2013 07:10 PM

you said that you have an LS-1 engine.
Those engines are over 300 HP and fuel injected,with the GM hot cam and cleaned up cylinder heads they make over 400 HP with fuel injection.
Spend the money to make the factory FI work in your car and have an easy 400 HP engine that idles smooth and gets decent mileage,or convert to a carb and make less power?

hcompton 01-02-2013 07:16 PM

12:1 is too much i think. Not sure it will work with pump gas. 10.5:1 should be good with pump gas. 11.5:1 should be good with good pump gas and proper tune. 12:1 would be as high as i would go with street engine. If its race only then go max compression and run race gas.

Basic rule of thumb is if you drive it to the track pump gas if you trailer it to the track then run race gas and hogher compression to take full advantage.

Ls motor is roller so there are some better options for cams. With roller and poor heads i would be looking at some cams that have wider powerband that starts low and has some punch left up top(4500rpm).

Either way i would recommend some new heads from after market. GM makes some great big heads that wprk well for all flavors of v8s. Brodix and edelbrock are also very nice.

hpete 01-02-2013 07:45 PM

You need to figure out exactly what you have. A 97 silverado came with neither an ls 1 or tbi.

hcompton 01-02-2013 07:59 PM

Yep looks like its a gen II vortec. Not an ls vortec. GenII and genIII blocks look very different. Its very easy to spot an LS block once you seen a few pictures of one.

Here is a link to what gm sells. I would look at the fast burn or vortec heads both will make north of 400 hp with good cam. The vortec heads would be the better choice for efi. Sky is the limit for carb. I like 18 degree stuff but its a ton of money to swap it all over.

Cylinder Heads

Your stock heads are going to fizzle out at 300 or so hp. You will want to use a cam that matches up to that a little better.

Hope this helps.

ap72 01-02-2013 08:34 PM

gen 2 is LT engines, the sbc Vortec is a Gen 1 engine. The 193 head is on a gen 1 TBI engine and as stated is good for about 300-325hp.

Rmatt87 01-02-2013 08:45 PM

Thanks to you all for the feedback. Do any of you know if i can still use this block with the same set up as listed above with a good set of aftermarket heads?

Rmatt87 01-02-2013 08:53 PM

Never mind the truck is a 1997 Chevy C/K 2500. It comes with a 5.7L V8 that is Throttle Body injected.

Valkyrie5.7 01-02-2013 09:38 PM

Quote:

Originally Posted by Rmatt87 (Post 1629961)
Never mind the truck is a 1997 Chevy C/K 2500. It comes with a 5.7L V8 that is Throttle Body injected.

As said before: No, it's not. There was no TBI 96+ Pickups, nor are 193 heads off a 96+ engine. Your top end at the very least is model year 1995 or older for a truck. You may be confused because you're getting back about as much misinformation as you're giving.

GunnerTHB 01-02-2013 10:40 PM

96-98 was Gen I Vortec, not TBI. The head casting #'s should end in 062 or 906 for the 350 and 059 or 520 for the 305. Gen III Vortec truck engines were 4.8L, 5.3L, and 6.0L.

TBI head casting # ended in 193. It makes a nice paperweight.


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