Crank Swap experiment

[66ford]

Have a new project for my 66 f100, I built and installed a 390 in it this time last year, specs:

.020 over 390 w/2bbl pistons
D2te heads, nothing special done to them
Crane Cam 343941 Advertised Duration 272/284, Lift .533/.563
stock valvetrain
Duraspark dist w/MSD 6A
Edelbrock streetmaster, stock no porting
Holley 750Vac w/1in open spacer
Truck headers
C6 w/stock converter
3.70 rear gears runs around 3k rpm @70mph

Truck runs good on the highway, seems kinda mushy down low,
Ended up with hairline cracks near the freeze plugs that are now leaking, so I have decided to clean up a short block I had in the shop, drop in a 428 crank ive had for 20 years and make a ~418 out of it.

Replacement engine:
.040 over block with silvolite 1139 pistons
Its cleaned magged and ready to go, I believe the 1139 pistons will work fine with the 428 crank.  Question is, what can i expect with swapping in the 428 crank with the same cam and intake? Would I gain anything by installing a performer in place of the streetmaster? Do I need to get a higher stall converter (2200-2500?)

Thanks
Howard

[KMcCullah]

If your .040 over block hasn't been decked, the Silvolite 1139 pistons should sit about .010 below deck. Any idea how many CC's they hold? Might want to try a .030 head gasket if the dish is deep. 10cc's or more.

Those D2 heads have a lot of room for improvement. You might consider a CJ valve upgrade. I'd keep the Streetmaster if you do a valve upgrade. Otherwise I'd go with the Performer intake. I think it would help your low end performance.

I think your torque converter will work as is. With a longer arm, your gonna get a little higher stall out of it.

[66ford]

Thanks for the reply. The piston head volume shows as 9.5cc, and I didnt have the block decked-im going the poor-boy route here.

Here is what i got from a compression calculator on the silvolite web site

[BattlestarGalactic]

Four years back I rebuilt the motor in the wagon.  All I did was put a 4.25 crank in it(same heads, cam, intake, same compression ratio).  Wow, does that long arm make a difference.  I know I'm leaving ton of power on the table, but I was on a budget too.

That streetmaster is likely why you are lacking low end power.  The 3.98 crank will likely help cover that up and make a noticeable improvement all around.

[KMcCullah]

I'm coming up with about the same CR. No worries there assuming your combustion chambers are 72ish CC's. I'm coming up with a lot less DCR tho. Does Crane want your ILC at around 106 or less? I'm guessing it already has 4* ground into it. That's how I figured it anyhow.

I almost went with the same cam your using when I did my 416. Went with the baby Thumpr instead.But our short blocks are pretty similar.

[66ford]

Im thinking that the cam has 4 deg advance in it. Now that i think about it, i installed a timing set with multi keyways on the crank gear, and I set it at 4 deg advance, so i guess im running it @ close to 8 deg advance.  I know advancing cam timing gives more low end but sacrifices top end, moves the rpm range around.

Its crazy to think that .20 longer stroke makes that much difference.

I have a performer that i can install, but not sure if it would help or not. I may swap out the 3.70 gears for 3.25 or even 2.75 at a later time. This is my weekend car show cruiser, so not a racer.

[BattlestarGalactic]

I picked up 75 hp!  No other changes(really, nothing).  Granted you aren't going to see that kind of improvement....but you will notice a much stronger pull down low.

If you go with faster gears, I would try the Performer.  The gears will really need torque to get you moving.

[66ford]

when i go back together with the 418 I will put the crank timing gear in at 0* and just use the built-in 4* in the cam. Not sure if im staying with the streetmaster or swap to the performer, have to make a game-time call on that.

Thanks for all the input.

Howard

[TorinoBP88]

Switch to a dual plane intake is you want to get rid of the mashed potatoes below 2500 rpm.

But if you run a 416 as is, you will still be happy. 

Degree your cam, make sure you are at about 104* on the intake center line.

[jayb]

I don't think the Streetmaster is the problem.  My brother's Cougar with a 428 and a cam similar to yours has no low end torque mushiness, fries the tires from an idle with the stock converter.  More cubes will help, and probably some carb tuning also.  However, the Performer intake will make more low end torque than the Streetmaster, if that is your goal.  Problem is that manifold falls on its face after 3500 RPM or so.

[BattlestarGalactic]

Wow..didn't know those Performers fell off so early?

[KMcCullah]

  Problem is that manifold falls on its face after 3500 RPM or so.

I don't know what untouched D2's flow but I'd bet you'd be lucky to wheeze 400hp out of them. The Performer is like the perfect intake for untouched D2's. I think the Streetmaster is too much for untouched D2's. I haven't tried this particular combo, just a hunch. 

[My427stang]

This is very old data, and when I say old, it was 20-something Ross doing the swap and I just turned 49 LOL.  However, I am with Jay, the Performer falls off too quick for anything more than a stock 352/360.  I really consider it a weight savings only

I ran my 270H 396 w/ stock D2 heads and headers in my truck with a T intake, then swapped a 428PI (very nice change from the C5), then bought a Performer FE when they were new, swapped it on a Saturday, then swapped it back the next day, because iit lost power on the whole curve.  Between those two events was trying to tune it to get some power back because this was the "newest FE intake on the streets" and I couldn't believe how much power it lost.

Later, when the base of the PI rotted, I swapped a Street Dominator and couldn't tell the difference from the PI.  That intake stayed on there until I built the 445 a few years back and I sold it on the forum.  In fact, I wish I would have kept it.

D2s and C8AE-Hs flow about 210-230 cfm depending on valve job, Joe would know more on the intake numbers, but my experience is that they really like the SD and SM.

[66ford]

Thanks all for the info. I think I will stick with the Streetmaster, and im thinking by the additional stroke plus the increased compression it will make a marked difference

I was on the silvolite calculator yesterday and if i plugged in all the right numbers, the combo im currently running with the 2bbl pistons has a fairly low CR-right around 8.5 so thats probably the issue. this new combo calculates out to around 10-1

[66ford]

Another question on this build--

To recap, Im building a 410 and have a street master and a performer to install on D2te heads. Will I gain anything by going with a Performer RPM on those stock heads(no port matching)?

thanks
Howard