Engine Finishing up motor and trans swap; questions and advice

Justin87

5 Year Member
Aug 7, 2017
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Hello All,

Been a while since I have posted. Had a baby 9 months ago, been pretty busy. :rlaugh:

Anyways, about a year ago I got picked up a new motor and transmission for my 90 GT from a friend of mine. He bought them brand new and ended up never using them.

The motor is:
  • DSS cnc 20 race-prep 306
  • Trick Flow Twisted Wedge Heads
  • X303 Cam
  • 1.6 roller rockers
  • Explorer intake
The transmission is a built C4, with a 2800 stall.

I have gotten to the point with the build where I need advice about a few key parts. I want to get the thing running, I realize eventually I'll need proper tuning, but id say right now my goal would be to get it moving.

Questions:
  1. I apologize for sounding like a TOTAL newb among so many experienced foxbody guys but... how do I know what sized injectors to buy? I have tried a few calculators online, including the chart on LMR's website but I don't really know what to expect HP wise so I am not sure what to order. (related information the car does have a 300 lb/hr fuel pump)

  2. I know the injectors have to be calibrated with a matching mass-air meter. I'm looking for recommendations/advice about brands, who do you guys like?

  3. Once I get injectors nailed down, do I need to update the fuel rails? I'm under the impression that unless I upgrade the lines from the tank all the way to the motor, this can be an ineffective modification, but again, I am very much a newb in this department.

  4. Same question about brands, who do you guys like for fuel rails and pressure regulators?

  5. How vital is a new TB and EGR spacer? I know if I had a better intake manifold they would be a serious restriction but considering all I have right now is the explorer intake (which is admittedly not the best flowing anyways) I'm wondering if they might not be super vital and maybe I could save myself a few bucks and skip those. Eventually, I'm going to run a better intake manifold but for right now this is all I can do.

  6. Can / should I use the stock distributor?
The car still needs a few things like hoses, a fan and fan clutch, drive shaft and a host of other odds and ends but in my opinion those are all relatively simple by comparison.

I have been doing a lot of research in previous threads but some of them are a touch on the older side, so I figured I'd also post a fresh topic too.

Any help would be greatly appreciated. If you have questions about what I am asking, I can definitely clarify. Apologies for the long posting.

Thank you

-Justin

Pic of how the engine sits now with intake and wiring mocked up.
IMG_6448 copy.jpg
 
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You'd be safe running the 24lb injectors and MAF. The stock mustang TB will be a choke point but the car will run fine for the street. The explorer intake should have about a 60mm bore TB. The mustang one is smaller. Not a big deal.

The stock fuel rails support up to 500hp. No need to change them. I like ProM for MAF.
 
You'd be safe running the 24lb injectors and MAF. The stock mustang TB will be a choke point but the car will run fine for the street. The explorer intake should have about a 60mm bore TB. The mustang one is smaller. Not a big deal.

The stock fuel rails support up to 500hp. No need to change them. I like ProM for MAF.

Thanks for the quick response!
 
You'd be safe running the 24lb injectors and MAF. The stock mustang TB will be a choke point but the car will run fine for the street. The explorer intake should have about a 60mm bore TB. The mustang one is smaller. Not a big deal.

The stock fuel rails support up to 500hp. No need to change them. I like ProM for MAF.

Any thoughts on the dizzy? I gotta assume at this point, while the motor is nicely built, the stock one would also do fine. Just not sure about the gear. I know with certain cams the distributor gear needs to be changed.
 
If you have a roller cam for a 5.0 mustang then the stock gear is fine. The stock distributor is the best. Make sure to look down in it below the plate the rotor button sits on. The pickup is down there and it should look like clean plastic. If its powdery its bad. It should spin freely. A bunch of these old distributors start seizing up. Just takes some penatrating oil and a few turns to free them up usually.
 
So which TW heads are these, and what’s your intended use? The 3 speed auto makes me wonder if this is a race or street car.

$700 to $800 seems like a lot for a different intake to me. If this is a street car, and if you like the black Explorer intake’s look, I’d save some money and port what you have.
Tmoss can port the lower half of what you have to match the heads and flow much better. And the upper can be opened up to match a bigger TB, and then you can smooth airflow and enlarge the throat as far as your tools can reach. A set of big, Chinese long calipers and dividers shaped like the ones in the picture can keep you from running into the bolt holes while taking as much of the bumps out to match the TB opening. If you have an air compressor, an air grinder, a few bits, some sanding wraps, and some WD-40 are not very expensive. It’s time and knowing what to leave that’s the expensive part of porting. My grinder came with a Campbell H. compressor kit, but hopefully you can get one that is rated for your air compressor’s output.
I’d skip BBK’s MAF’s. I got three that went bad. The first two were under warranty. They were picky about being clocked before the electronics went out.
I went with a C&L body rated for the injector size and a new Delphi stock style electronics insert. It’s running well.

When you upgrade the TB, check out how to fix the whistle problem before installing it. The BBK one I have whistles when the IAC is working, as can many other brands. It’s not annoying enough to take off and fix yet, but had I known ahead of time, it would have been prepared before assembly.
 

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If you have a roller cam for a 5.0 mustang then the stock gear is fine. The stock distributor is the best. Make sure to look down in it below the plate the rotor button sits on. The pickup is down there and it should look like clean plastic. If its powdery its bad. It should spin freely. A bunch of these old distributors start seizing up. Just takes some penatrating oil and a few turns to free them up usually.

Yup its an x303 cam with Ford racing lifters so it's a roller. Thanks for the info about the distributor, I'll definitely check that out before I put it back in.
 
So which TW heads are these, and what’s your intended use? The 3 speed auto makes me wonder if this is a race or street car.

$700 to $800 seems like a lot for a different intake to me. If this is a street car, and if you like the black Explorer intake’s look, I’d save some money and port what you have.
Tmoss can port the lower half of what you have to match the heads and flow much better. And the upper can be opened up to match a bigger TB, and then you can smooth airflow and enlarge the throat as far as your tools can reach. A set of big, Chinese long calipers and dividers shaped like the ones in the picture can keep you from running into the bolt holes while taking as much of the bumps out to match the TB opening. If you have an air compressor, an air grinder, a few bits, some sanding wraps, and some WD-40 are not very expensive. It’s time and knowing what to leave that’s the expensive part of porting. My grinder came with a Campbell H. compressor kit, but hopefully you can get one that is rated for your air compressor’s output.
I’d skip BBK’s MAF’s. I got three that went bad. The first two were under warranty. They were picky about being clocked before the electronics went out.
I went with a C&L body rated for the injector size and a new Delphi stock style electronics insert. It’s running well.

When you upgrade the TB, check out how to fix the whistle problem before installing it. The BBK one I have whistles when the IAC is working, as can many other brands. It’s not annoying enough to take off and fix yet, but had I known ahead of time, it would have been prepared before assembly.

I have heard those BBK throttle bodies, sometimes they even sound like an old super charger or something.

These are Trick Flow Twisted Wedge Heads.

In terms of it being a street car or a race car, I'd say it'll be a street car and once it's all set up and properly tuned it will see it's fair share of time at the local drag strip. Nothing competative, just for fun. By NO means is it going to be a daily driver or anything. Honestly, I don't plan on keeping the C4 forever, but the previous owner had it built at the same time as the motor so I knew it would strong enough to handle the engines power.
 
Which twisted wedge heads are they ? If the heads are too big with the gt40 explorer intake it'll kill some air velocity. Car won't run perfect but should run.
 
TFS makes several models with that brand name that flow differently. 11r, 170, 190 pop up on their page right off the bat, and there were their old high port heads. Accurate answers need some more info.
 
TFS makes several models with that brand name that flow differently. 11r, 170, 190 pop up on their page right off the bat, and there were their old high port heads. Accurate answers need some more info.

My apologies, I thought I included that in the original post. These are their original twisted wedge 170 heads. 58cc combustion chamber I believe.
 
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Which twisted wedge heads are they ? If the heads are too big with the gt40 explorer intake it'll kill some air velocity. Car won't run perfect but should run.

My apologies, when the previous owner ordered this motor from DSS I don't think trick flow had so many styles of heads. (2008-ish)

Anyways, these are the 170 heads. 58cc combustion chamber I believe.
 
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You'll be fine with the explorer intake for now.

Aftermarket throttle bodies can whistle. I run a 75mm TB and spacer on my turbo car. When the tune was off it would whistle. Once everything got dialed in better it stopped.

As stated above TMoss can port that explorer intake to work well with the TF170s.

I've got TFS heads port matched to a Holkey Systemax intake. Seeing the professional work makes me not even want to attempt it on my own.

The stock computer plays nice with injectors 30lbs or smaller. The newer style injectors atomize the fuel better but require adapters or modifications to the harness.

The stock 225hp was fun in a fox mustang ...your engine will make your car more fun to drive than that.
 
You'll be fine with the explorer intake for now.

Aftermarket throttle bodies can whistle. I run a 75mm TB and spacer on my turbo car. When the tune was off it would whistle. Once everything got dialed in better it stopped.

As stated above TMoss can port that explorer intake to work well with the TF170s.

I've got TFS heads port matched to a Holkey Systemax intake. Seeing the professional work makes me not even want to attempt it on my own.

The stock computer plays nice with injectors 30lbs or smaller. The newer style injectors atomize the fuel better but require adapters or modifications to the harness.

The stock 225hp was fun in a fox mustang ...your engine will make your car more fun to drive than that.

Yeah, I am hoping this should make it a pretty quick little car. I'm thinking about going with a ratchet shiftier to make the C4 more fun to drive.

I have seen that some of the injector kits come with adapters for the newer style injectors (EV-6 I think they are called?) Is it worth going with the newer style vs an OE style injector for a fox mustang? Price is obviously a factor but if it's truly worth the money I'm down.
 
If you're not going to add boost in the future 24lb injectors with the fuel pump you have and your stock rails will work fine.
When my car was MAF I went through a few brands before I found one that worked well, it was Pro M.
Your engine looks great !
 
I haven't ran ev6 in any of my foxes yet. People say its worth it though. The idle quality is supposed to be a lot better...and a better burn at the spark plug.

I know people personally that use them. I run ev1 42lb but I use them on a turbo car. Will be upgrading to ev6 soon.
 
Explorer intake has a 65-67 mm opening. It comes with a 65 mm throttle body. It flows just like a cobra intake.
I am running 58 cc twisted wedge heads myself milled to 58cc's. Stock castings were 62 and 60 from the factory! YIKES!

I'm a little in the same boat as you.. injectors. If you are buying them I would get 30's. Leave a little wiggle room. If you already have 24's and the correct maf.. then run them

Just torqued the heads down last night after pulling my hair out measuring for pushrods. I went with 6.80
 

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Explorer intake has a 65-67 mm opening. It comes with a 65 mm throttle body. It flows just like a cobra intake.
I am running 58 cc twisted wedge heads myself milled to 58cc's. Stock castings were 62 and 60 from the factory! YIKES!

I'm a little in the same boat as you.. injectors. If you are buying them I would get 30's. Leave a little wiggle room. If you already have 24's and the correct maf.. then run them

Just torqued the heads down last night after pulling my hair out measuring for pushrods. I went with 6.80


Nice! Love the coverplate on the intake! I can tell you are also better at spraying wrinkle black then I am too! :D
 
If you're not going to add boost in the future 24lb injectors with the fuel pump you have and your stock rails will work fine.
When my car was MAF I went through a few brands before I found one that worked well, it was Pro M.
Your engine looks great !

Thanks! Let's just hope she run as good as she looks :D