Help me plan my engine build

[Sluggie24]

So in a year or so I'm planning to build, or have an engine built, or re-build this engine, for my 04 GT auto.

It has a AA intercooled Vortech V3 Si on it only pushing 10-11psi. Makes 370 rwhp and 350 rwtq now.(safe tune) Might try to to get it to 14 psi with built engine but my power goal would only be maybe 450 rwhp.

I need opinions from people who have been down this road before on what is worth spending money on and what isn't. I'm trying to do this as cost effectively as possible since it's just a fun street car and I'm not out to set records at the track.

I'd like to strengthen the bottom end so it will be problem free (and handle more boost/timing) and while it's apart get the heads ported and stick in some blower cams.

Is it worth spending the money for a 5.0 big bore block or should I just stick with the 4.6? I don't know if the power gained will be worth the extra expense.

How about strokers?

Do I need a forged crank with an auto that won't be running slicks?

Which rods and pistons would give me the best bang for the buck while still being strong enough to handle my potential power with reserve?

I've been looking at the rotating assemblies MMR offers and their 600 and 750 kits seem to be reasonably priced. Anyone have any experience with them? Their built engines seem a bit higher than I want to spend but maybe the easiest way to go.

Sorry for all the questions but I like to figure out what direction is best early so I can plan and save. Any input anyone could give would be great!

 

[Scud2]

I'm not the best at this type of thing but if you want to spend as little as possible...my advice:
Smaller pulley for more boost.
Think about air to air intercooler.
Snow meth injection kit...Super easy install and big hp gains.
450hp can be a tricky thing for the 4.6...

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[DSG2003Mach1]

to build a motor it seems like youre gonna spend a bunch of money to only go to 450. You could drop in a 4v cobra or mach motor and make that (although thats about as high as youd wanna go). A drop in terminator motor would be an option but the low compression would be an absolute dog out of boost with a centri.

for a budget option used terminator or boss rods are a popular choice. You might also look into Molnar connecting rods.

 

[Scud2]

to build a motor it seems like youre gonna spend a bunch of money to only go to 450. You could drop in a 4v cobra or mach motor and make that (although thats about as high as youd wanna go). A drop in terminator motor would be an option but the low compression would be an absolute dog out of boost with a centri.

for a budget option used terminator or boss rods are a popular choice. You might also look into Molnar connecting rods.

Exactly my point on the 450hp. Prob a little too much to completely trust the stock internals. So if you build it get to at least the 500 club

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[Sluggie24]

Would 500 rwhp be obtainable with ported stock heads, blower cams and 4 more psi of boost if I stayed with a 4.6? Or would I need more displacement? I'm trying not to go too crazy with boost so the engine stays reliable for the long term.

 

[Scud2]

Would 500 rwhp be obtainable with ported stock heads, blower cams and 4 more psi of boost if I stayed with a 4.6? Or would I need more displacement? I'm trying not to go too crazy with boost so the engine stays reliable for the long term.

Every engine will put up different numbers. I know you know that. But as far as what you said...in my opinion...was to keep on a budget. Adding a smaller pulley and an intercooler will work wonders. Easiest thing to do is get close to 410 to the wheels that way with a tune and call it a day. The intercooler will eat some boost so lowering a pulley is a must. Maybe get like 11-12 lbs with cooler air and throw long tubes on there. If you strengthen the bottom end and touch everything else as you go it's super smart. Upgrading as long as you are there is a dream of mine. But not the most cost effective. I'm just thinking out loud. If you stay under like 420 you bottom end should be fine on a dd. My opinion...

Would 500 rwhp be obtainable with ported stock heads, blower cams and 4 more psi of boost if I stayed with a 4.6? Or would I need more displacement? I'm trying not to go too crazy with boost so the engine stays reliable for the long term.

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[Scud2]

Would 500 rwhp be obtainable with ported stock heads, blower cams and 4 more psi of boost if I stayed with a 4.6? Or would I need more displacement? I'm trying not to go too crazy with boost so the engine stays reliable for the long term.

Oh. Also I have the same engine. V3 as well. I got to 386rwhp. Then I added meth to cool the air and add some fuel. Pretty easy install and a retune. 406 now with 390 tq. I'm happy. I just made sure to put iat sensor after meth to read cooler air Temps. Meth turns on at like 4 or 5 lbs. If I drive normal then it does not drink it too quick. Problem is driving normal. Lol

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[Sluggie24]

Well I did install the CX racing Intercooler kit and changed from the stock 3.6" to the 3.33" pulley already. (I knew the intercooler would cause the boost to drop a bit) I told the tuner to tune it really safe however because the bottom end was still stock.

I know there is more power in it as it sits if I have him write a more aggressive tune but since I'm thinking about using this block to build a forged lower I don't want to risk damaging it until I'm ready to build.

I also understand that the auto trans soaks up considerably more power than a manual trans does. If the car had a manual I figure it would be around or slightly over 400 rwhp right now.

 

[Scud2]

Well I did install the CX racing Intercooler kit and changed from the stock 3.6" to the 3.33" pulley already. (I knew the intercooler would cause the boost to drop a bit) I told the tuner to tune it really safe however because the bottom end was still stock.

I know there is more power in it as it sits if I have him write a more aggressive tune but since I'm thinking about using this block to build a forged lower I don't want to risk damaging it until I'm ready to build.

I also understand that the auto trans soaks up considerably more power than a manual trans does. If the car had a manual I figure it would be around or slightly over 400 rwhp right now.

I'm thinking you are dead on there. All depends on budget really. I got my motor to 400. Goal complete. Now I work on appearance.

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[Sluggie24]

So if my plan is not to go much above 500 rwhp at best, does that mean I don't need a forged crank? Can I just get away with forged rods and pistons? Maybe something like MMR's 600 rotating assembly kit?

 

[jaxbusa]

With a street friendly goal in mind, I would get forged pistons, better rods and mild cams. Put on the next smaller sized pulley you can get for the charger. Stock heads and crank will be fine at that level. You will have a reliable combo for a reasonable price. I don't know your other supporting parts but if you try for 500 hp or more you will likely need new maf, injectors, fuel pump and better flowing heads. Then you will strain your high mileage transmission. It will be a money pit.

 

[Sluggie24]

I'm building another 4R70W trans right now that with all the upgraded internal parts should handle 700-800 hp along with a PA 2400 converter. Those will go into the car this spring.

As far as other performance parts the car already has: shorty headers, high flow cat x pipe, flowmaster cat back, trick flow upper plenum, 75 mm t-body, 39 lb injectors, focus pump, KB BAP, CX racing intercooler kit, BA-2600 MAF and 3.55 gears. I know making more power will require better injectors and pump.

After looking at MMR's rotating assembly offerings I'm thinking I might just go with their 600 kit, or talk to a good engine builder that a co worker knows, about piecing together good pistons and rods and re-using my current crank.(after cryo hardening) that builder also does head porting with a flow bench for only $800 per pair. Throw a pair of MMR's custom blower cams in with a smaller pulley and I think I would be done.then with a more agresive tune I should get into the mid 400's easily.

 

[Deceptive]

Find an aluminum block if you can to reduce some weight and use stock crank.
$200-300

Used SVT/Manley H Beams
$300-350

New pistons.
$500-600

Use stock heads.

Used 60lb injectors
$250-300

Stock Cobra dual fuel hat
$50-100

Black306 Fuel Pumps
$120

Upgraded FPDM
Forget cost, I got a used one cheap

If you go for about 10:1CR and up timing you should make 450+ at the tires with about the same boost.


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[Sluggie24]

Thank you for that info.

Will I absolutely need a dual pump setup or is there a large single pump that would work since I already have a BAP?

No head porting needed?

 

[Deceptive]

Thank you for that info.

Will I absolutely need a dual pump setup or is there a large single pump that would work since I already have a BAP?

No head porting needed?

While some people are ok with a BAP, it is a band aid. You are forcing a pump to do something it was not meant to do. My dual pump and modified FPDM cost me under $300.

Porting the heads will help but add cost.


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[Sluggie24]

Well I picked up a Teksid block from someone I know to start off my build. Damn those blocks are light!

So my long term plan for this year will be:

Punch block .020 over, line bore the mains, true the decks, hot tank and replace all the plugs.(possibly send the block to get cryo hardened)

I think I've settled on getting a forged and balanced rotating assembly from MMR because they are a complete done package ready to stick in the block. (Will wait till Black Friday sale) I'm just debating on which power rating to go with. I'm thinking the 750 4.75L stroker so it's overbuilt a bit with a forged crank.(might send that all out for cryo hardening too) I'm also not sure which compression pistons to go with that will give me good street performance while safely taking higher boost. Maybe 9.5-10?

Since I don't drive the car in the winter next winter I will pluck the old engine and send out my PI heads for porting and rebuild. Throw them on the new block with MMR blower cams, bigger injectors and pump, and a smaller blower pulley which might mean an 8 rib conversion.

I'm thinking, hoping, this will leave me with 12-14 psi and 500 rwhp through my new beefed up 4R70W auto with a more aggressive tune that the new engine can better handle.

Also debating the twisted wedge street burner intake but I'm not sure if the cost will be worth the power gain over the stock lower and twisted wedge upper.(it would look good though lol)

Any opinions on this plan? Anything else I should consider?

 

[01SilverGt]

You car does not need a motor for 400rwh or any of that. My car makes 500wheel on a stock short block with ported heads full exhaust and a d1sc. If your only looking to make 450wheel leave the short block alone. Blower cams, ported heads with valve springs, air to air all you need 12-13 pounds


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[StrayBullitt]

Blower cams, ported heads with valve springs, air to air all you need 12-13 pounds

... And a good safe tune

 

[Sluggie24]

I think a built bottom end will allow my tuner to get more aggressive with the tune and get much more power out of the combo though won't it?

Plus I already have the Teksid block and dropping around 80lbs off the front end is very appealing beyond the strength aspect. lol

 

[01SilverGt]

Absolutely with a built motor and a fuel system 500 wheel should be np through an auto you may have to up your boost. I have a different centri than you. But yea 500wheel 13.3 pounds 12 degrees timing 93 octane.


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