Engine Can yall help me add another 100HP?

silverlx50

15 Year Member
Apr 4, 2007
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I am looking to add more power to the LX vert. It's at 540 whp now and I know I am leaving some on the table with my blower and intake. I'm exploring swapping intakes for the Holley Systemax II and sending my S Trim, that's making 12 lbs, to Vortech and either upgrading the internals to the Si trim or changing over to a T Trim (I'd rather not go this route just for the sake of $$$$).

This is my current motor setup:

347 Dart Liberator from Fordstrokers
Stroke 4.030
Wiseco 2618 Forged Dish Pistons (20cc, TFS) 4.03
Compression 9.3:1
Trick Flow 11R 190 Heads
93 Cobra Upper intake and Explorer lower
Vortech V1 S Trim at 12lbs (bought in 2005)
BBK Equal Length headers
2.5 H Pipe through Spintech Mufflers
Quarter horse tune through Elite Performance in Littleton Colorado

I am 6000 ft above sea level and 91 octane is the best around.

Any idea how much power can I get from the intake swap and a blower upgrade?
 
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Come on. You don't need any more hp! That's plenty. :hide:

In these cars you are probably correct. I just hate to have to potential to squeeze another 50 hp out of at least a good intake. The car runs like a beast and I finally found the right tire / wheel combo so that it actually hooks. This Cobra intake has to be at its limit (out of the box). Plus, it's crazy the S550 guys making over 700 whp with just a blower and supporting suspension mods...
 
Swapping the intake and upgrading the blower to an Si wheel should get you close if not over your goal. You're leaving a lot on the table with that cobra intake and explorer lower with your 347 and those 11R heads. With just an intake swap, I could see you gaining 40+ rwhp. You should see an additional 2+ psi with the Si upgrade and the same pulley setup, though you might see a little less since you will be removing some restriction with the new intake.

Is your V1 the standard gearbox version? If so, you will be at or slightly above it's max rating @640 rwhp so you will need to look at upgrading if you ever want to go further. Also, what cam are you running?
 
Oh, and here is a test I had seen AFM do between the cobra intake and the systemax. This was on a N/A 306 motor and they gained 35 rwhp with just an intake swap to give you an idea. Just scroll down to the description and check out the dyno graphs.

 
Swapping the intake and upgrading the blower to an Si wheel should get you close if not over your goal. You're leaving a lot on the table with that cobra intake and explorer lower with your 347 and those 11R heads. With just an intake swap, I could see you gaining 40+ rwhp. You should see an additional 2+ psi with the Si upgrade and the same pulley setup, though you might see a little less since you will be removing some restriction with the new intake.

Is your V1 the standard gearbox version? If so, you will be at or slightly above it's max rating @640 rwhp so you will need to look at upgrading if you ever want to go further. Also, what cam are you running?
Ok thanks. I think that's about what I was expecting. Yes it's the standard gearbox version. I attached the Comp cam specs...
 

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I was reading about HP gains on intakes. And a very similar setup, 347 blower they were testing on gained 30hp if i remember correctly. Maybe it was 50. Going from the gt40 to systemax.

Ima do my own test soon, stock bottom end, cam. Stock heads/intake. = xxx

Vs. Ported E7's w/ a systemax 2 = xxx. Lookn for 40hp. We'll see.
 
do you have a copy of the dyno graph for this engine? we are basically running the same cam and i want to see the torque curve.

Here is the new run with 11-12lbs boost. Outside temps were about 25*. Shop owner says their reading is generally 30 off when its this cold. We are at about 6000 ft above sea level. I read you can take about a 3% loss for every 1000 feet of elevation, could that be correct? That is another 99 hp if the car was at sea level.
20200226_100342.jpg
 
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Here is the new run with 11-12lbs boost. Outside temps were about 25*. Shop owner says their reading is generally 30 off when its this cold. We are at about 6000 ft above sea level. I read you can take about a 3% loss for every 1000 feet of elevation, could that be correct? That is another 99 hp if the car was at sea level.
20200226_100342.jpg
Not bad at all, with better air and sea level i would expect some better numbers but i dont believe 100hp to be the case. either way it looks like a fun ride.
 
Not bad at all, with better air and sea level i would expect some better numbers but i dont believe 100hp to be the case. either way it looks like a fun ride.
It runs great, I can tell the difference in the low end and top end rpm's with the Holley instead of the Cobra. It pulls much better to 6300 instead of leveling out early with the Cobra intake. I feel like the Cobra had better low end torque which seemed to break the tires loose a hair sooner then with the Holley. I did add full length MM subframes too so that may have also helped but traction is fantastic all the way through with the Hoosiers and this setup.
 
Just for some sort of a reference, mine is a 331 with an Si-trim and twisted wedge 170 heads. I had a trick flow street burner intake with 1-5/8” shorty headers and a 2.5” exhaust and made somewhere around 550whp (around 200-300 elevation, not spraying methanol injection) and I went to a systemax intake with with 1-3/4” long tubes and a 3” exhaust and it made 625whp without spraying the methanol.
 
Did you have Tmoss port the lower intake? And is the upper matched for the throttle body and blended in as far back as your tools can reach and as close to the bolts as you dare?

I will soon have an extra Corvair motor that will add 80 hp in the trunk. That should not break the 302 block.