Adding 100+ HP to this combo

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F-BIRD'88
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Re: Adding 100+ HP to this combo

Post by F-BIRD'88 » Thu May 10, 2018 12:32 pm

The real compression ratio of this engine based on what you have now posted about it is 8.94:1 with a .040" gasket. Needs to be 10.50:1.

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Re: Adding 100+ HP to this combo

Post by F-BIRD'88 » Thu May 10, 2018 1:12 pm

Here is a engine where you could apply David Vizards 128 formula to the cam selection
and drag test it as is against the current camshaft.

My math suggests a 104.4 LSA camshaft. I'd also suggest knocking back on the duration too to pump lots of torque into this slug.
104 to 105 LSA installed a bit advanced say 268 ish to 275 ish real seat to seat lash point running duration.
I suggest a short duration tight lash style solid lifter cam. (Comp cams MH series or XTQ series or extreme energy solid lobes series on the suggested LSA.)
Move it around a bit and play with the lash a bit to find the sweet spot
and let the ET slip speak.

As DV has said the real value is when a 3rd party has success using his simple 128 formula to get a better cam choice. Might end up with a strong 13sec performer with a good torque curve on this car engine as is. or with other very cheap changes. (used RPM intake)

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Re: Adding 100+ HP to this combo

Post by F-BIRD'88 » Thu May 10, 2018 1:59 pm

You'd also want to test some collecter extensions
to let the re cammed engine be all it can be.
pretty cheap mod.

As I said you could use the current cam with added solid lifters to adjust the real running seat to seat duration and net valve events and real verified installed position to get as close to the suggested new valve events of the new 128 formula cam as possible and see if the engines/cars perf (et slip) moves in the right direction.. Again a cheap mod.

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Re: Adding 100+ HP to this combo

Post by rfoll » Thu May 10, 2018 4:38 pm

travis wrote:
Thu May 10, 2018 8:57 am
I’m sure 4.56’s would be a lot of fun at 80mph keeping up with traffic 🙄

Doesn’t matter anyway...this thing is junk. Turns out his “425hp street/strip” eBay special is nothing more than a cheaply built stock replacement cast dished pistoned 2 bolt 357 with pistons .048” in the hole, 58cc chambers, barely over 9-1 compression, and a big cam. Judging by the bearings and main caps, it clearly wasn’t happy being zinged up to 7k rpms with the stock crank and rods.

The guy just left here with his stuff...not a very happy camper I might add.
One of my friends acquired an ebay 383 that was supposed to be built with Scat crank and rods. We pulled the pan and found a stock crank and 305 rods. The roller tips on the shiny blue rockers were beat to death.
So much to do, so little time...

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Re: Adding 100+ HP to this combo

Post by gmc406 » Sat May 12, 2018 11:00 pm

rfoll wrote:
Thu May 10, 2018 4:38 pm
travis wrote:
Thu May 10, 2018 8:57 am
I’m sure 4.56’s would be a lot of fun at 80mph keeping up with traffic 🙄

Doesn’t matter anyway...this thing is junk. Turns out his “425hp street/strip” eBay special is nothing more than a cheaply built stock replacement cast dished pistoned 2 bolt 357 with pistons .048” in the hole, 58cc chambers, barely over 9-1 compression, and a big cam. Judging by the bearings and main caps, it clearly wasn’t happy being zinged up to 7k rpms with the stock crank and rods.

The guy just left here with his stuff...not a very happy camper I might add.
One of my friends acquired an ebay 383 that was supposed to be built with Scat crank and rods. We pulled the pan and found a stock crank and 305 rods. The roller tips on the shiny blue rockers were beat to death.
Did you go after the seller? That’s horse sh!t.

Too bad for your friend.

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Re: Adding 100+ HP to this combo

Post by rfoll » Sun May 13, 2018 11:05 am

He got the motor from a friend who had bought it and let it sit for several years, much too late for any reparations from the eBay seller. Fortunately the friend was good enough to give him back some of his money in exchange for the bad rotating assembly. He kept the block, AFR heads, and Lunati cam.
So much to do, so little time...

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Re: Adding 100+ HP to this combo

Post by travis » Tue Jun 19, 2018 9:49 am

Update...

I ended up building a low buck 388 for this guy with s considerably smaller cam. 9.7 compression, scat crank and rods, forged dished Icon pistons, Vortec heads with screw in studs and some light blending and cleanup work, performer rpm, and a crane 228/234@.050 hft cam on a 106 lsa installed at 102.

I thought it sounded really good...not near as ratty sounding as before but a healthy crisp muscle car idle. The guy came to pick it up this morning and immediately started bitching...too small of a cam, won’t make any power, etc. I tell him drive it for a few days...if he doesn’t like it I’ll swap it for free. He reluctantly paid me...pissing and moaning the whole time. He leaves here, gets down to the main road about 1/4 mile away, and lays into it. I can hear him hammering on it several times and then abruptly letting off. A little later he comes back by and says never mind...this thing is f’ing AWESOME 🙄 Good thing I put a couple hundred miles on it over the last few days.

Gawd I hate people sometimes

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Re: Adding 100+ HP to this combo

Post by RevTheory » Thu Jun 21, 2018 11:32 am

No shit huh. Sounds like you nailed it, though =D>

Any idea where the peaks were?

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Re: Adding 100+ HP to this combo

Post by travis » Thu Jun 21, 2018 11:59 am

I’d guess HP peaks around 5400-5600...that feels like where it’s starting to nose over a bit. It still goes 6200+ real easy...I didn’t push it any harder myself though.

I asked him if he was going to yank the engine and take it back to the dyno....he said hell no...but it’s going back to the track when it’s not 100+ degrees outside.

And it sounds like traction has become a bit of an issue :lol:

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Re: Adding 100+ HP to this combo

Post by Carnut1 » Thu Jun 21, 2018 12:08 pm

Happy customer is all that matters. Nice!
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Re: Adding 100+ HP to this combo

Post by F-BIRD'88 » Thu Jun 21, 2018 4:07 pm

Put some gears in that 3800 LBS sled and it will perform.
Needs some 4.30's (tall tires) or 4.10's (Short tires)
you want it to just exceed 6200 rpm thru the traps at the track (1/4 mile).
You need leverage(gears) to move the 3800LBS quickly.

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Re: Adding 100+ HP to this combo

Post by Carnut1 » Thu Jun 21, 2018 5:16 pm

F-BIRD'88 wrote:
Thu Jun 21, 2018 4:07 pm
Put some gears in that 3800 LBS sled and it will perform.
Needs some 4.30's (tall tires) or 4.10's (Short tires)
you want it to just exceed 6200 rpm thru the traps at the track (1/4 mile).
You need leverage(gears) to move the 3800LBS quickly.
This is something I could never get straight. If it having traction issues with 3.42's how will 4.30's help?
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Re: Adding 100+ HP to this combo

Post by novadude » Thu Jun 21, 2018 5:53 pm

F-BIRD'88 wrote:
Thu Jun 21, 2018 4:07 pm
Put some gears in that 3800 LBS sled and it will perform.
Needs some 4.30's (tall tires) or 4.10's (Short tires)
you want it to just exceed 6200 rpm thru the traps at the track (1/4 mile).
You need leverage(gears) to move the 3800LBS quickly.
Of course the owner won't ever want to drive the thing because it will be spinning 3500 rpm at 65 mph in the slow lane.

Nevermind… I forgot that this is the speedtalk forum where there is no room for anyone that doesn't want to set a class record or post hero dyno numbers. :roll: :lol:

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Re: Adding 100+ HP to this combo

Post by F-BIRD'88 » Thu Jun 21, 2018 6:27 pm

its simple quick Weight transfer at launch. Get some sticky tires if you want o go fast.

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Re: Adding 100+ HP to this combo

Post by travis » Thu Jun 21, 2018 6:30 pm

This is a street car...he wants to run it down the strip just to see what it does. The 3.42’s are staying...judging by the squirrelly black marks he left out here it doesn’t need more gear on street tires! Besides...legal highway speeds around here are 70-75mph in a lot of places...meaning traffic can be upwards of 85-90mph for long stretches. 4.10’s or 4.30’s would be miserable.

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