Ok so I have a pretty well built 390 that was done last summer and it has pretty good power. When I was aquiring parts for the build I always wanted to find a 428 crank to make it a 410. Well I have some options now on building a 410 or a 428 for the spring. I found a 428 standard"A" block from a guy for a cheap $200. Now I would bore the block .30 over and I have some .30 over stock type cobra 428 pistons lined up for cheap ready to go as well. The crank I would need which I'd buy new from SCAT. Now the guy with the block says 410's really aren't much less power than a 428 from what he's built and dynoed. He also has a set of brand new cast .40 over pistons for a 410 he'd sell for $50!! Now do I build a 410 out of my already done 390 block with a .40 over bore(making a 418?) or get the new 428 block and build that out of my 390 with the cobra .30 over pistons. Either way somethings getting bored out.

My 390 build:
stock heads rebuilt and decked no porting
edelbrock performer 390 intake sides milled to fit heads
650 offroad edelbrock carb
crane 343941 cam with valve springs
meling high volume std. pressur pump
crane cam fire ball ignition
headers
.30 over forged pistons

Plan on transfering most parts over minus the obviuos...gaskets,bearings,pistons,crank

 

I do know about the external balance thing I would balance the 390 flywheel the machinist told me it can be done.
The motor would be in my truck with 44" tires and I think the higher torque at lower rpms is the ticket.

 

Go with the 428, especially if you can find some CJ heads, because "There is no replacement for displacement."

 

73 ford guy, I am confused. All along I thought a 410 was built by using the smaller bore 390 block with a 428 crank.

How does one use the larger 428 bore block with a 428 crank and come out 410?? scratching head





John

 

I'd say it depends on how much of a performance engine you want. 410 pistons are hard to find, especially forged ones, and consequently are usually quite expensive, but forged are what you want for a high performance engine.

Those cast 410 pistons would be good for an engine more or less stock, or slightly modified. Be careful though....you need to determine what compression ratio those pistons will give you, espcially useful info when you decide to pick a cam.

If you want to build a tire squeeler, I'd go for the 428. Only because with a cast piston 410, you probably want to keep the power mods down.

Mind you, you could probably sell that 428 block for quite a bit...maybe enough to cover the parts for a 410 with forged pistons.

You will need to get the rotating assembly balanced, and that relies on knowing the piston weights as well as getting the 428 crank and 390 flywheel balanced.

Sidenote: If you go for a 0.030 overbore 410, you really will have 416...close to a stock 428.....but then again, you need the 428 bored also.....

 

I would do the 418, your 390 is already at .030, and 390 blocks aren't big money like 428's- buy the 428 block on general principle for that price, and stash or sell it- I would never bore a good std 428 block, especially to .030, just because I could get pistons cheap- there aren't too many std 428 blocks around any more, and you'd instantly devalue the block by doing the good 'ol boy corner machine shop "we'll punch 'er .030 and build it to the max" number on it- nowadays there are many more options in pistons sizes & methods than going right to .030 over on a rare block.
And you won't feel any difference in a pickup between the 410 and 428 setups- except in "wishfull thinkin" horsepower
You'd also want to check the date codes & such on that 428 block, if you got lucky you might do real well on reselling it- just don't do anything to it, leave it as-is

 

If you're buying a SCAT crank, how far can you go in stroke for minimal extra $'s? Well, I guess that means special pistons and rods, eh?

 

Good points. I'm leaning towards just doing the 428 it really won't cost much more to build and it definetely has the"cool factor"! I think it needs a bore buddy says so a standard bore isn't achievable. I'll have to check the compression on those 428 cobra pistons I want to keep it 10:1 and under to run regular or mid grade gas. I'm changing to 5:13 gears soon here as well right now my motor runs in lower rpm range like 2500,2800ish. I wanna bump it up to around 3200/3500ish??? To get in the power range of the 428. Sound about right...

 

428s make all their torque at under under 3400 rpm (CJ) and closer to 2800 for the standard 428. Why would you want to start at where the torque curve ends?

 

Peak torque at 2800???? That's just getting going! So what I should stay with my 4:10 gears and keep it that low? 5:13's are pretty much a must for 44 " tires. It will bump up my rpm but also should makes it easier on the driveline.

 

That's a very good price for a 428 block.

 

There were 2 CJ and SCJ performance gear ratio available. A 3.91 and a 4.30 to 1. Of course these were in the Torino and Mustang bodied cars. But my 1969 stock 428CJ Ram Air Cobra Fastback (Torino body) with 4.30 and G60X15 tires went thru the traps at 100.55 mph at 6000 rpm (where the C-6 shifted at in drive) and did it in 14.07 seconds. My 1969 428SCJ (Crane cam) Notch back Cobra with toploader, with the same 4.30 gears and 28" tall 9" slicks would carry the front tires a car length off the line and ran 12.70 at 118 mph.

 

That's not perzactly accurate- if you ordered the 3.91 or 4.30 gears, they automatically required/were part of the Drag Pack option, including the oil cooler and "SCJ" engine, which was the same as the regular CJ except for the LeMans rods and rebalanced crank assembly with the cookie cutter dampener spacer. You could get most any gear ratio in a CJ car, but the 3.91 or 4.10 cars became an SCJ with the cooler and HD engine parts. CJ packages were available in the '69-'70 Mustang and Cougar and '69 Fairlane and Cyclone
My 4-spd '69 Fairlane Cobra still has it's original 3.00 posi rearend, as did my buddy's '70 Mach1, so both were "Cobra Jet". I'm putting together an SCJ for an original car right now, a '69 Mach1 that I've been involved with for 33 years, and is an original 3.91 Drag Pack car. CJ and SCJ heads, intake, block, carb, & cam are all the same, pistons, rods, crank & dampener spacer are different, and the special oil filter adapter to accomodate the oil cooler is different

 

Im going to look at the 428 block tomorow nite. Guy says he has 3 of them. I phoned the guy back with the .30 over cobra jet pistons and asked the compression ratio of pistons. He says he recalls they are a 10.3:1 and he uses the same ones in his car and truck with a 428 and he uses pump gas. does this compression sound about right?he says pistons are just the standard 4 eyebrows stock ones. O he wants $150 for all 8 with wristpins no rods. He also says all 390 rods newer than 67 from a truck are the strong ones so not to worry about mine.
My heads are a d2teaa that again are shaved down some # not know as i never did it. Am I able to put the larger CJ valves? into these with the 2.09 intake 1.66 exhaust for better flow?Will my compression be even higher because my heads are shaved a bit or is it just for the cj head you get the 10.3:1 ratio.My cam is good for 8.75-10.75:1 compression range with a cruise at 2600-3000. Id like to port my heads a bit to match the gasket size if it helps when its all out. Would I be wasting my time or should I find cj heads? Also will I be under carbed with my new 650 edelbrock or can i jet up a couple sizes or go bigger like a 750?Im asking you guys the pros and thanks for the help

 

I knew that, but it was not necessary for the point I was making. My fastback, auto car came with the 3.00 gears and I got clocked at 144 mph by the CHP and that was about a 1000 rpm from max. The stick shift car had all the drag pack crap on it, which may or may not have made the motor more reliable.