Engine choice: Heads or stroke?

[120mm]

As I said in my other thread, I am planning to build an economy FE to put in a Shelby Cobra replica. I have a very strict budget, and doing the math, and a bit of research, I've decided I can afford one of two combinations:

1. 390 stock stroke with 10:1 compression, Edelbrock or Streetmaster heads and a cam to fit.

2. 390 stroker with similar or slightly lower compression, stock heads and a cam to fit.

Both would have an Edelbrock RPM manifold and carb to fit.

Based on a bunch of advice, I'm looking at a 3.73 final diff ratio, either WR Toploader or TKO 600 RR and a goal of under 2300 pounds, dry.

I was planning initially to do the 390, but then I talked to a couple guys who liked strokers with stock heads and read this article:

http://www.mustangandfords.com/how-to/engine/1410-how-to-build-a-390fe-stroker-500-pound-feet/

The question is, how relevant are good heads and a stroked crank to a car that will be assertively driven between 30-65 mph (ok, maybe a titch more than that, but other traffic and police enforcement are scarce out here), on typical country roads for 90% of use?

Alternatively, there could be a third or even fourth choice out there I am overlooking.  Any and all relevant input would be appreciated.

[wsu0702]

Assuming that you are starting from scratch I would say option #2 is the better play and bang for your buck.  There is no replacement for displacement when it comes to making power and contrary to popular belief most run of the mill stock FE heads have fairly decent flow numbers.

[120mm]

Assuming that you are starting from scratch I would say option #2 is the better play and bang for your buck.  There is no replacement for displacement when it comes to making power and contrary to popular belief most run of the mill stock FE heads have fairly decent flow numbers.

Yes, to starting from scratch.

I started my build planning thinking I had an engine already, but it walked away on me.

[plovett]

If there ever was a combination that was right for combination 1, this is it.  You have a light car with fairly low gearing, and a big block in it.  You won't be hurting for low rpm power.

I would much rather have the 390 with better heads than the 445 with stock heads.  This is a car that will want to rev.  The heads are the main key to power.   More displacement, especially with lo-po heads will pump up low rpm power.  This combination doesn't need or want the extreme low rpm power that a stroker with "small heads" will provide.

While it's true that most non-exotic factory FE heads are decent, they aren't awesome either.  An unmodified Edelbrock head is roughly equivalent to a factory 428 CJ head,  maybe a tad better.

If you were building an engine for a truck or a Galaxie or maybe even a Fairlane, I'd say go for combination 2 for sure.

JMO,

paulie

[blykins]

I'm for #2.   

Anything above 320 hp will make a Cobra flat-out boogie. 

If you put your money into the bottom end and built a 445, even with a big cam and factory heads, it will make a lot of horsepower and torque for a Cobra.  The intent here is that if your money tree grows later on and you decide you want more power, it's a whole lot easier to bolt on a set of aftermarket heads than it is to pull an entire engine and stroke it. 

I had a Cobra before I got married.   They are so light that almost any engine at all will get you killed.

[120mm]

If there ever was a combination that was right for combination 1, this is it.  You have a light car with fairly low gearing, and a big block in it.  You won't be hurting for low rpm power.

I would much rather have the 390 with better heads than the 445 with stock heads.  This is a car that will want to rev.  The heads are the main key to power.   More displacement, especially with lo-po heads will pump up low rpm power.  This combination doesn't need or want the extreme low rpm power that a stroker with "small heads" will provide.

While it's true that most non-exotic factory FE heads are decent, they aren't awesome either.  An unmodified Edelbrock head is roughly equivalent to a factory 428 CJ head,  maybe a tad better.

If you were building an engine for a truck or a Galaxie or maybe even a Fairlane, I'd say go for combination 2 for sure.

JMO,

paulie

That was the initial plan, for sure. It's also the first advice Brent Lykins offered me over a year ago, when I first started talking about this project. Of course, he offered that advice when I "thought" I had a rebuilt 390 waiting for me.

I'm for #2.   

Anything above 320 hp will make a Cobra flat-out boogie. 

If you put your money into the bottom end and built a 445, even with a big cam and factory heads, it will make a lot of horsepower and torque for a Cobra.  The intent here is that if your money tree grows later on and you decide you want more power, it's a whole lot easier to bolt on a set of aftermarket heads than it is to pull an entire engine and stroke it. 

I had a Cobra before I got married.   They are so light that almost any engine at all will get you killed.

Or if you were spending money on the stroke, just to get to/surpass a "magic" number like "427". I had not really considered building stroke first for a "multi-stage" build.

I know, it's dumb to think that way, but there it is. But the way I look at it, it's a big toy, and if a 427-ish+ displacement FE makes it a better toy, and the stock heads don't hold it back too much, why in heck not?

Brent, I think we're pretty much done with the engine decision-making aspect, here. Now to do the work to earn the money and to get home so I can start the build.

Stroked 390 + rebuilt stock heads + cam to match + TKO RR + 3.73 rear gears. Throw that all in a lightweight Cobra replica build w/IRS and it should be fun.

Thanks!

Drew

[My427stang]

I like the stroker too, assuming rebuilding the stock heads is much cheaper than out of the box Edelbrocks.  If not, I would delay dropping the heads on and just bite the bullet for a set of Edelbrocks on the stroker.

I like the TKO-600RR with a 3.73, often people overgear the RR.  You'll have 10.71 compound 1st gear ratio, and 3.05:1 5th.  I'd even argue, depending on tire size and cam choice, you should go taller gear.  A 3.50 would make it more controllable in 1st and still give you plenty of gear in 5th at 10:1 1st and 2.87 in 5th.

[Gregwill16]

Build the engine right the first time with options 1&2 with the savings of going with a toploader and 3.50 rear gear.

[120mm]

I like the stroker too, assuming rebuilding the stock heads is much cheaper than out of the box Edelbrocks.  If not, I would delay dropping the heads on and just bite the bullet for a set of Edelbrocks on the stroker.

I like the TKO-600RR with a 3.73, often people overgear the RR.  You'll have 10.71 compound 1st gear ratio, and 3.05:1 5th.  I'd even argue, depending on tire size and cam choice, you should go taller gear.  A 3.50 would make it more controllable in 1st and still give you plenty of gear in 5th at 10:1 1st and 2.87 in 5th.

Rebuilt stock heads are about $800 cheaper, total, from what I can find. Having said that, the build is still about 10 months out. I "may" be able to free up some additional budget between now and then, and "might" be able to do both stroker and heads.

There are several other priority items that need to be taken care of first.

Build the engine right the first time with options 1&2 with the savings of going with a toploader and 3.50 rear gear.

I like where your head's at. The key issue I've found with the toploader is that it has the potential of being just as expensive as the TKO. A Kee Toploader is $2100, and a top of the line Shifter assy is $500. Which takes it to TKO territory. You can purchase a rebuilt one for $1300, or a used one for around $900-1000. You still have to find a shift assy, and you "hope" it's a good unit.

These numbers come from internet research, though; I'd be very happy for different data on toploader price.

I'm not poo-poo'ing your idea; I'm explaining why I'm currently leaning toward TKO 600 RR.

[My427stang]

If you can get a set of good heads cheap, you'll be down on peak power, but it'll run strong, just lean toward it petering out at higher RPM.  Just be sure you do not get C7AE-A, C8AE-H, or D2TE-AA because Cobra headers will likely not seal to the low ports.

As far as power, remember, a decent rule of thumb is 2 X intake flow for a peak HP number and the entire curve can be affected.  So a 260 cfm Edelbrock compared to a 240 cfm iron can be up to 40 horsepower and the Edelbrock will have weight savings on the nose of a light car. 

[jayb]

Option 2.  Once you have the car running either way, you will want more  .  If you start with option 1, you will have to pull the whole engine and rebuild from scratch.  With the option 2 short block, you can leave everything in the car and just pull and replace the heads.  A much easier proposition...

[Gregwill16]

Toploaders are everywhere and a good one for your "temporary" needs should be $600-800 plus shifter. Build the engine right and be done and temporarily run a good used toploader until you can afford the TKO setup and the toploader will resale for what you have in it.

[120mm]

Toploaders are everywhere and a good one for your "temporary" needs should be $600-800 plus shifter. Build the engine right and be done and temporarily run a good used toploader until you can afford the TKO setup and the toploader will resale for what you have in it.

I will make an effort to look around for one, then.

Thanks!

Drew

[120mm]

So... Any suggestions on where to look for parts for a stroker build?

Right now, I've seen Keith Craft has a prepped block for $1529 and Clegg has Scat 4.25 internally balanced rotating assemblies for $1778.

Throw an Edelbrock 2044 Top end kit on that for $2298, and it seems I should be most of the way there for $5605.

Rocker assy/rods    $265
Oil pump kit             $80
Timing cover      $80
Harmonic balancer   $115
Distributor      $130
Valve cover      $200
Canton Oil Pan   kit   $412
Water pump      $105
Expansion tank   $50
Fuel pump      $130
Flywheel              $100
Alternator bracket   $20
Alternator              $50

$7342 without carb, pulleys or rubber bits, so call it $8000

Bellhousing              $625
Clutch                      $350
Toploader/shifter     $1000
Driveshaft                $350

Wheels                      $2049
Tires                         $1200

Call it $13,750 for drivetrain, once nuts and bolts are thrown in.

That's within shouting distance to my pre-stated budget, right there.

[plovett]

Why not just put a turbodiesel in that "sports car" along with a C6 and a 2.73 rear gear?  What's next?  Fuel injection and a radio? 

My mom in law would like it. 

Of course, I didn't realize there was an option 3 or 4 from the original question.