If I were looking for 250 FWHP, I'd find a donor foxbody and get the 5.0 out of it. Put a nice mannered cam in it with add headers and you'd be darn close! Maybe even swap over those GT40 heads you mentioned.Could probably get away with converting it to carb as well.

Last edited by Raymond_B (12/19/2019 2:38 PM)

50-100 hp is a big jump!

Gaba wrote:

Raymond_B wrote:

If I were looking for 250 FWHP, I'd find a donor foxbody and get the 5.0 out of it. Put a nice mannered cam in it with add headers and you'd be darn close! Maybe even swap over those GT40 heads you mentioned.Could probably get away with converting it to carb as well.

So what I have is an engine out of a 92 .. was thinking of throwing Gt40P heads , cam kit and shorty headers to see if it’ll do what I needed . But somehow I thought , let’s c how much more would it cost to go to a 300-350+ hp.. seems like a big jump..

But again, apparently finding a good set of gt40p heads apparently is hard ... and then they need new springs to match the cam...

Still weighing options

Gaba, if you go with gt40 heads, check out alexparts.com. he sells the springs you need to upgrade. If you want to be sure you're getting the correct Springs, send him your cam card specs. Has great customer service. I've used him twice on both 5.0's I've built, no issues.

http://www.mustangandfords.com/how-to/engine/28898-400-hp-302-small-block


This guy.......(the late) Joe Sherman has the "touch" for building HP.  May be a little more than you want to build butt----- "a few points from this guy...a few points from that guy"...mix'em all up and you-be-scoot'in!  A good indication what a SBF is capable of.
6sal6

350-400hp is doable but do you need it? You're chassis needs to be up to the task as well. Your motor is only going to make as much power as the suspension and tires can put to the ground. You need to have a over all package.

I run a junkyard GT40P with a 5.0 factory cam in my 66 Mustang, wide ratio 4 speed and 2.80 gears soon to be 3.55's. These are light cars you don't need a ton of power to have a good time. My motor maybe makes 280 hp. If money is limited and you already have the heads and other parts why not forget the 350-400 hp goal and make the most of what you have? So my suggestion is like I said use the parts you already have. I'd spring money for a custom ground cam though. Later on if you want you can make upgrades.

Counterpoint is, why spend money twice on the same thing?  I'd rather drive my car than tear the engine apart (though my comments below may call that into question momentarily). 

BUT, its all about what you want it to do.  I don't really do the whole "cruising" thing.  So if you do, then my advice probably isn't for you.  My vehicles are all street driven 99% of the time, but I do like having the ability to head to the track on a Wednesday night, make a bunch of good passes, and drive home. 

What constitutes a good pass?  I'll admit that's gone down a lot over the years.  Used to be 14.50s were fine, until I started running 14.20s, then when I hit 13.90s in a Diesel truck I had to step up my cars' game because that's just embarrassing.  Then the big Diesel went 13 flat with the new sticks and bigger turbo, so the fun cars are all going to have to be able to run 12s, which is what I'm building engines for now.  Surely that leads to 11s at some point.  Oh well, its a sickness for sure, but one I have no interest is seeing in remission.  Who says you can't get faster as you get older?  As the saying goes "We don't stop playing because we get old.  We get old because we stop playing."

In the end, create a goal, make a plan, and stick to it.  Where guys go wrong is starting an engine build with neither.  Moving targets are much harder to hit.  If you'll be happy with a sub 300HP engine build one, but if you suspect you won't; don't.  The problem with combinations is that they work.  I've witnessed many guys ruin good combinations in search of more power, and been guilty of it myself.  The whole car does have to be up to the task.  Brakes, suspension, driveline durability can all come into play.  Years ago, sick of breaking parts, I started upgrading everything but the engine first in preparation for more power.  This led only to less downtime and frustration. 

TKOPerformance wrote:

Counterpoint is, why spend money twice on the same thing?  I'd rather drive my car than tear the engine apart (though my comments below may call that into question momentarily). 

BUT, its all about what you want it to do.  I don't really do the whole "cruising" thing.  So if you do, then my advice probably isn't for you.  My vehicles are all street driven 99% of the time, but I do like having the ability to head to the track on a Wednesday night, make a bunch of good passes, and drive home. 

What constitutes a good pass?  I'll admit that's gone down a lot over the years.  Used to be 14.50s were fine, until I started running 14.20s, then when I hit 13.90s in a Diesel truck I had to step up my cars' game because that's just embarrassing.  Then the big Diesel went 13 flat with the new sticks and bigger turbo, so the fun cars are all going to have to be able to run 12s, which is what I'm building engines for now.  Surely that leads to 11s at some point.  Oh well, its a sickness for sure, but one I have no interest is seeing in remission.  Who says you can't get faster as you get older?  As the saying goes "We don't stop playing because we get old.  We get old because we stop playing."

In the end, create a goal, make a plan, and stick to it.  Where guys go wrong is starting an engine build with neither.  Moving targets are much harder to hit.  If you'll be happy with a sub 300HP engine build one, but if you suspect you won't; don't.  The problem with combinations is that they work.  I've witnessed many guys ruin good combinations in search of more power, and been guilty of it myself.  The whole car does have to be up to the task.  Brakes, suspension, driveline durability can all come into play.  Years ago, sick of breaking parts, I started upgrading everything but the engine first in preparation for more power.  This led only to less downtime and frustration. 

I sure do think my goal is not the strip yet. I have NEVER in my life been on the strip to make a pass. DO I intend to one day.. Yes.. But I dont think this build is being done for that. This thread and all the info you and all others have posted in it is already invaluable. I dont think I will have the permission yet to spend a good chunk of cash on something like heads.. Which BTW would be AMAZING!!!

It comes down to this being my goal for my 65 FOR NOW (next 10 years).. So here goes : RELIABLE RELIABLE RELIABLE  Date night rides with the wife.. RELIABLE Weekend rides with the kiddos (who are 3 and 2 right now, and cannot get enough of the mustang already), being able to take it to cruise 100+ mile rides, and enjoy the view and the ride, all in the while being able to have enough power in the engine, that If I floor it, it responds, and , i can feel it take off!! and once in a while, when I am alone in the car, break the tires loose on take off, and burn some rubber.... seriously that is all .. for now!  As I get older, like you said, TKO , more power will be added! :D

My gearing like I said is 3.25 right now.. Dont like the one legged burn outs but I will save some money for now and keep it there. wide ratio AOD.. Shelby dropped, lowered springs, with shelby spec adjustment of alignment. 5 leaf mid eye on the back. Bilstein street valved shocks all the way around, Borgeson Steering assist, front disks. It makes for a very comfortable drive.. esp for the front two passengers.

Car looks good, rides good, but there is no power esp on take off.. Could I just tune my carb and timing just right , and get what I want, probably!! But there has been a lot of overheating issues I have  had in the last 6 years I have had this car.. and they have made the car VERY unreliable.. .. ... Now that I have the 24" radiator ( as of like August) and 7 blade flex fan in there, the car has not misbehaved at all no matter how much I hammer on the throttle, with AC on  or off.. or whatever. Now it has been sub 70degrees so I am waiting for the 80+ weather to hit for me to get the real report.

All that to say,  I dont want to build the engine in a vacuum. If I am asking for y'all's advice, I need to let y'all into my thought process. I hope y'all read it all and tell me what you think.

Huskinhano : I hear your advice, and I am leaning towards it.. But lets c. I do not have any heads right now. Its a short block ... but lets c.. where the deals and wallet leads me LOL

Last edited by Gaba (12/20/2019 11:30 AM)

Reliability is also paramount for me.  I've taken my, 67 on several long trips in the past couple years, trips I never would have even considered in years past because the car was geared wrong for it without OD.  With the addition of the T5 I have very little fear about its reliability.  All my vehicles have to be able to make those kinds of trips, and my DD and wife's DD need to be able to do even more (like family trips to Maine).  I don't know if I'll ever take one of my classics on such a trip, but I do entertain the idea.  If not now, possibly in years to come. 

The strip is a great time if you have a good one near you (I fortunately do).  I've tried for two straight years now to get down there the end of October before they close for the year with my oldest son, but both times they've closed the track without warning for dubious reasons.  When they reopen in the spring I'm going to make a point and get back.  I want to re-baseline my '67 so I'll see how much of an improvement I've made to date and how much more the eventual 347 swap really is. 

My final bit on heads would be that if you can find a good set of GT40Ps and can live with the power you can get from a stockish (for the GT40P heads) cam they aren't a bad way to go.  The problem I have is they are +/- 20 years old now, and I surely don't trust the guys on Craigslist who say they only have 50k on them, aren't cracked, etc.  I'd have to get them checked and do some work, and then WYAT takes over and poof!  $1,000-$1,200 up in smoke on a set of outdated iron heads.  I had the same situation arise when I looked at GM Vortec heads for a 350 I was building years ago, and they were only $600/set new from the dealer, but couldn't handle the cam I wanted and couldn't breathe at higher RPM, so I bought my 6073 Edlebrocks that are on the 383 in my K5 right now. 

Keep an eye on Corral.net for a bargain deal on some heads.

josh-kebob wrote:

Gaba, since you aren't in a hurry, do take the time to list out the items you still need to complete the build. That way, you'll have a real idea of how much you'll likely end up spending on your engine build. Even a "budget build" will surprise you at how much money you'll end up spending. Take your time and accumulate the remaining parts you need. Get a line on a few machine shops in your area and compare prices and lead times.  There are going to be more hidden expenses as well. 

Maybe the best advice on here yet.  Having cost tracked a couple of projects over the years you'd be surprised at how much seemingly insignificant things can end up costing.  As an example, I've spent almost $180 on nitrile gloves on my '89 GT project thus far.  People would say "no way, that's insane!"  Its actually only 15 boxes at about $12/box.  When you're into dirty tasks like rebuilding the rear, trans, removing chassis grime prepping for undercoat, etc. you go through stuff like that quick.  Then there's solvents, fluids, etc.

I once heard take what you think you'll spend and double it.  Again, sounds crazy, but...

Increasing horsepower can reduce reliability.

$500 for a pair of cleaned , magnafluxed GT40P heads with stock everything (not rebuilt) ... good deal ?, bad deal?

Last edited by Gaba (12/21/2019 1:59 PM)

Rudi wrote:

Increasing horsepower can reduce reliability.

Interesting that I've seen this same picture about a dozen times when discussing the reliability of the stock 5.0 block.  IMO if this were common we'd see a lot more pictures of it.  Its starting to seem like it happened once and as a result a lot of people are scared.  I've got a buddy that has a 550HP blower motor built off a stock 5.0 block that's never failed.  I watched a guy run a 250HP shot on an otherwise stock 5.0 engine for years at the strip and it never failed.  Talking to the guys at DSS they basically say the limit of the stock block is around 600HP.  I don't think going from stock to 350 or even 400 is anywhere close to causing the block to self destruct. 

My thought is that this engine detonated bad, had a casting flaw somewhere and split in half.  I'm also wondering if it was just a guy who just wouldn't lift when he heard it knocking...