Another Mustang...

[Three50won]

Well, I sold my 95 a few months ago and I started craving another SN...so I found a guy selling a 94 GT and bought it this past Tuesday. The car has a CAI and a cat-back exhaust. Other than that it is bone stock. It has that awesome Mustang sound that we all love. The car runs good as is. The body is solid but it will need a paint job. The drivers door will need the hinge replaced and it needs some overall attention but nothing major. It is in DD condition. The car runs and drives good for its age and mileage.

My plans for it are to do some minor mods and enjoy the car. I plan to keep all the smog stuff including cats. And I plan to keep the stock heads, cam, and intake manifold. I do plan to do a moderate compression 331 stroker and a blower (with the stock top-end). I'm gonna use 3.55 gears and I might keep the stock header/H-Pipe set-up. I will see where those mods get me and maybe upgrade more extensively down the road.

You may be asking why I plan on using a stroker kit and S/C with smog equipment, stock HCI, exhaust manifolds, and H-Pipe. Sounds kinda silly right? Well I plan to do this because I want it to look like a stock engine with a blower. But I also figure that down the road I may wanna unleash all the power I'll be leaving on the table. When that day comes I can just do a top end kit since I'll already have a stroker engine. Another reason is because I wanna mod the car and make it as fast as possible while retaining that Mustang sound...for now!! I gotta say, I am in love with the way the car sounds. It sounds soo good that I like driving it almost as much as I like driving my Camaro!! So we shall see. I might start a build thread. Stay tuned!!

BTW, can you guys tell me how much I can mod without losing that traditional sound? I figure I will lose it if I swap the OEM top end but what about ported heads or GT-40 stuff? Any advice?

 

[ProKiller]

i wouldn't even waste your money with the 331 if you plan on putting the blower on it anyway. just put the blower on it and get a good tune. but any blower will whistle at least a little bit. with stock-ish exhaust it will be more noticeable. but if the point is to keep it stock looking, then a blower is not going to look at all stock. if that's the plan, i would say do a remote mount turbo. if your dead set on the 331 with stock parts, i recommend at least getting some thumper E7 heads and intake.

 

[Three50won]

I want the engine to look stock. So it will look like a stock engine with a blower. Will I lose the Mustang sound with the head/intake swap?

 

[JordanB21]

I want the engine to look stock. So it will look like a stock engine with a blower. Will I lose the Mustang sound with the head/intake swap?

I'd stroke it out higher than a 331 if it's suppose to be a sleeper with a charger. Of course, your money and thought.
Intake swap I don't see why it would effect the sound.
course, are you keeping the stock look on the engine bay and outside or just outside? Because if it were the engine bay I wouldn't go further than a cobra intake/explorer.

 

[Three50won]

I want the engine to look like a stock 5.0 with forced induction!!

 

[JordanB21]

I want the engine to look like a stock 5.0 with forced induction!!

and the exterior you're leaving or modifying?


I have this theory where the car has to have a themed appeal and flow correctly all around, interior, exterior, and engine bay, sometimes suspension.
Again, stroke out a bit larger in my opinion.

 

[Three50won]

I'm fine with keeping a stock exterior. It has tint and I may do some rims and a hood but that's about as far as I'll go. I also have a 351 block sitting around...!!

 

[RangerJoe]

Something to consider from a guy who has done a 331 with iron heads (Ported GT40's). Your compression is going to rise to the point of max compression with iron heads and pump gas if you use flat top pistons. This will hinder your goal of using a supercharger. You can use dished pistons to bring the compression down for the blower, but if you ever lose the blower and want to go N/A with aftermarket heads, they you will have a low compression stroker, which is not really ideal. Now, if you plan on alminum heads and a blower down the road, then go ahead and do the dished pistons.

For example, I had my heads milled to clean them up. I asked the machinist to mill as little as possible. I ended up with 62CC chambers. I have 4cc flat top pistons with valve reliefs with my 331. This gives me a compression ratio of 10.15:1, which I run on 93 octane and 14 degrees of timing. If I had gone with a 347, my compression was going to be way to much to safely run pump gas, especially on those 95+ degree days.

I'm not knocking the stroker idea at all, in fact, I understand your idea behind it. I needed to rebuild my bottom end, and a stroker was only a few hundred dollars more than doing a 306. I couldn't afford aluminum heads at the time, so I reused the GT40's, but one day I plan on putting aluminums on there and hopefully making some good power.

I just wanted to point out a few things with the route you had in mind. You may have already thought of these things. If so, I offer it as food for thoughts and not criticism.

Good luck with your project!

Joe

 

[Three50won]

Something to consider from a guy who has done a 331 with iron heads (Ported GT40's). Your compression is going to rise to the point of max compression with iron heads and pump gas if you use flat top pistons. This will hinder your goal of using a supercharger. You can use dished pistons to bring the compression down for the blower, but if you ever lose the blower and want to go N/A with aftermarket heads, they you will have a low compression stroker, which is not really ideal. Now, if you plan on alminum heads and a blower down the road, then go ahead and do the dished pistons.

For example, I had my heads milled to clean them up. I asked the machinist to mill as little as possible. I ended up with 62CC chambers. I have 4cc flat top pistons with valve reliefs with my 331. This gives me a compression ratio of 10.15:1, which I run on 93 octane and 14 degrees of timing. If I had gone with a 347, my compression was going to be way to much to safely run pump gas, especially on those 95+ degree days.

I'm not knocking the stroker idea at all, in fact, I understand your idea behind it. I needed to rebuild my bottom end, and a stroker was only a few hundred dollars more than doing a 306. I couldn't afford aluminum heads at the time, so I reused the GT40's, but one day I plan on putting aluminums on there and hopefully making some good power.

I just wanted to point out a few things with the route you had in mind. You may have already thought of these things. If so, I offer it as food for thoughts and not criticism.

Good luck with your project!

Joe

Hey Joe, thanks for taking the time to give me some advice. Question tho...how would the compression have increased with more cubic inches? I would think that you would lose compression going from a 331 to a 347 if all else remains the same.

Anyway, I don't really plan on doing a whole lot of head swaps. I'm too afraid it will lose the sound that I wanna keep.

 

[RangerJoe]

Hey Joe, thanks for taking the time to give me some advice. Question tho...how would the compression have increased with more cubic inches? I would think that you would lose compression going from a 331 to a 347 if all else remains the same.

Anyway, I don't really plan on doing a whole lot of head swaps. I'm too afraid it will lose the sound that I wanna keep.

If you keep the piston CC's the same and you keep the cylinder head CC's the same, then increased cubic inches will increase compression. It increases because you are cramming more cubic inches of air and fuel into the same small place. Therefore, the compression if the air and fuel mixture is higher, because now 347 cubic inches of air and fuel are compressed into the same place that only 331 cubic inches were before.

http://www.wallaceracing.com/cr_test2.php

Joe

 

[Three50won]

If you keep the piston CC's the same and you keep the cylinder head CC's the same, then increased cubic inches will increase compression. It increases because you are cramming more cubic inches of air and fuel into the same small place. Therefore, the compression if the air and fuel mixture is higher, because now 347 cubic inches of air and fuel are compressed into the same place that only 331 cubic inches were before.

http://www.wallaceracing.com/cr_test2.php

Joe

Does this apply to modular engines? I ask because back when I did my 5.4 conversion in my 03 Mustang GT I was told that the compression ratio in the 5.4 will be lower due to the stroke. The bore was the same between the 4.6 and 5.4 blocks which meant I could re-use my pistons. The pistons I had were like an 18cc dish. And I was using 46cc Patriot Stage 2 heads. But the stroke and deck height on the 5.4 is longer. The compression on the 4.6 was about 9.0:1 but it dropped to about 8.5:1 with the 5.4. At the time I wanted to get pistons that would give me adequate CR in both engines...maybe even boost friendly. So if I had went to 10 cc DSS pistons then my CR on the 4.6 would have been about 10.5:1 and the 5.4 would have been about 9.5:1. I'm a bit confused...

 

[Three50won]

Oh, wait a minute...I'm sorry, I wasn't thinking fully...haha!! Yea you're right because if the deck height remains the same then the CR WILL increase...like you said. My CR decreased on the modular engines because the 5.4 had a taller deck height. Does that sound correct?

 

[RangerJoe]

Ok, not entirely. Lets say that you take one cylinder of your engine. The piston is at the bottom of its stroke and has pulled in the oxygen and fuel mixture. With the piston all the way down, this is the largest void or volume that this particular engine will see. So in theory, lets say that the combustion chamber volume, the cylinder volume, the valve relief volume and any other volumes created (thickness of gaskets or piston above or below the level deck of the block) all add up to be 100cc's of volume. Next, the piston drives up the bore and compresses all this fuel and oxygen in mixture into the smaller space of the combustion chamber. For this scenerio, lets say the combustion chamber is 10cc's. You have now taken 100cc's of volume, and compressed it into a space only 10cc's in volume. Therefore, you have compressed 10 times to volume into one space. 10:1 compression ratio.

Using this, if you had a 331 with 41.45 cubic inches of volume and compressed it into a 64cc head, you would get a certain compression ratio. Now, take a 347 with 43.38 cubic inches of voluem per cylinder, and cram it into that same 64cc head, the compression ratio will be higher because you put even more volume into the same place (41.45 vs. 43.38).

I hope this helps explain things a little bit. There are a lot more factors, but this is the basic idea and principle of the matter. You can Google it and find much more in depth explanations.

Joe