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Discussion Starter · #1 · (Edited)
The much anticipated build has begun, and I believe this build deserves its own thread, so here we go. To understand the decisions made in this build, you need to understand the goal, and that is to run 11.50s in average air with a 2.56 gear and the factory converter. I fully intend to achieve this goal on 225/70-15 Cooper Cobras, but I have Mickey Thompson ET street radials for if/when the need arises. The car can and will (still) be driven everywhere.

Running a 2.56 gear and factory converter presents a unique challenge in the first 100’ or so, or until the engine fights from 2000 rpm up to its torque peak. This means building an engine as mild as possible, with the caveat that the 2.56 gear acts like a 3.90 gear out the back door, so the engine can be no slouch when it comes to horsepower. I already gave the goal my best effort with my home ported, local built 496, but now it’s time to get serious.

To that end…late Feb/early March 2021, I convinced Mark to build a 4.375” stroke x 4.310” bore 510 CI engine inside a factory block. For those that know Mark, this engine surely wasn’t his first (or even second) choice for a 4100 lb street car running only 11.50s. After all, Victor’s 4200 lb ‘70 Monte Carlo already ran 11.0 @ 122 mph with a 622hp 467, 3.55 gears, and it still has A/C.

Anyhow, I know Mark likes the idea of taking an otherwise stock car, adding an engine, headers, exhaust, and a locker, and running deep in the 11s. Either that, or he wanted to put an end to my nonsensical “how many cubes can you build in a stock block posts?” :D Either way, I’m excited.

The rotating assembly is Scat with MAHLE -18cc pistons. In short, we’ll have no shortage of compression for the “small” cam, which is roughly 228/238 @ 0.050”.

The heads are oval port 049s, of course, which will be fitted with Manley Racemaster 11/32” 2.19/1.88 valves and Mark’s custom lightweight springs and retainer package. The idea is to achieve peak power under 6000 rpm and keep the valve train stable valve out the back door, up to about 6500 rpm (although we might not see that rpm at the track).

Mark is going to send a few photos along the alway and I’ll attend the dyno session when the time comes. Grab your popcorn, it’s going to be an exciting month.
 

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Following this one
 

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Discussion Starter · #7 · (Edited)
Man that isky cam sure is a sweet stick.
My build used the Isky 275/284, 228/238, .553/.578 cam.

In this case, it's a slightly smaller (duration), more aggressive (lift), Bullet HR, custom made to Mark's specifications.
 

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Discussion Starter · #8 ·
You are going to like it, and be amazed at the mph it will run. It will rev cleanly to 6700 rpm, no issue.
From my other thread...

Using Mark’s preferred Wallace calculator, and backing into the “observed” engine dyno hp…

ET-MPH-HP Calculator

4100 lbs, 119.46 mph = 538 hp (my local-built 496, in really good air)

Hoping to see between 122+mph (in average good air 1000-1500’)
4100 lbs, 122 mph= 574 hp
4100 lbs, 123 mph= 588 hp
4100 lbs, 124 mph= 602 hp
4100 lbs, 125 mph= 617 hp
4100 lbs, 126 mph = 632 hp

Do you all care to take a stab at the corrected power? (bear in mind, this is not a pure hp build, as stated earlier)

I chose the additional stroke to make the power/torque peak sooner and higher. We chose the smaller cam for the same reason. I'll be very lucky if I can get this animal off the line on the Coopers, even with the highway gears and stock converter.
 

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Oh boy... I'm in for 650hp/700tq
 
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What if the Easter Bunny brings you some 3.08 Richmond gears in a few weeks? :)
Totally kidding and hope to connect this Summer.
Build should be a very fun project. No doubt!!
 

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Discussion Starter · #12 ·
What if the Easter Bunny brings you some 3.08 Richmond gears in a few weeks? :)
Totally kidding and hope to connect this Summer.
Build should be a very fun project. No doubt!!
No chance for 3.08 gear. If not 2.56, 3.73 or 3.90.

I plan on being at Blue Suede Cruise, 7/29-7/31, along with about 25-30 First-Gen Monte Carlos. Stop by, go for a ride.

 
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Discussion Starter · #13 ·
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1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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Probably close.



It’s not a horsepower build, the cam is just too small.
Yeah but Marks building it :) Edit maybe I'm over guessing but it wouldn't surprise me to be close to 700 on both sides
 

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1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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1.3 X 511 = 664.3
1.35 X 511 = 689.85
 

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dragginwagon406 theres nothing wrong with your bore and stroke combination.
My 513 is almost identical,except that mine was a 0.070 overbore 4.32 with the 4.375 inch crank.
Mine is a strictly street driven car and it pulls great,although it doesnt like it much below 2-2200 RPM.
On the dyno we ran it up to 7000 RPM,the power started dropping after 6200 RPM,so I've set the rev limiter at 6500.
What length rods did you end up with ??
Mike Lewis put my rotating assembly together and he used 6.48 inch Molnar rods.
Looking forward to your results !!
Guy
 

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Discussion Starter · #19 ·
dragginwagon406 theres nothing wrong with your bore and stroke combination.
My 513 is almost identical,except that mine was a 0.070 overbore 4.32 with the 4.375 inch crank.
Mine is a strictly street driven car and it pulls great,although it doesnt like it much below 2-2200 RPM.
On the dyno we ran it up to 7000 RPM,the power started dropping after 6200 RPM,so I've set the rev limiter at 6500.
What length rods did you end up with ??
Mike Lewis put my rotating assembly together and he used 6.48 inch Molnar rods.
Looking forward to your results !!
Guy
6.385” rods.

We would have liked to have gone 4.350” bore but MAHLE doesn’t have this piston in that size.
 
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