Replacing motor in 95 GT - Need Advice

[the boost creep]

My '95 GT has been sitting in place for around 2 years now due to motor troubles and I'm finally ready to do the swap. My goal is for upwards of 400 horse all motor (don't want power adders). I would like to stick with a 331ci and not go for the 347 even though I'll probably hear otherwise. Also, I would like a fully assembled long block to take the guesswork out of the right combo.

So I came across CHP Motorsports PRO Street 331 and Street Fighter 331 each with options of dome, flat and reverse dome pistons. I see that reverse dome is for low compression as with power adders, flat is for close to stock compression and dome is for high compression. What would be the advantages/disadvantages of going with the dome top versus the flat? Also, I know 94/95 tuning can be tempermental with certain setups, so what would be the better choice in that respect: the Street Fighter (good for 550 horse) or the PRO Street (good for 800 horse).

I know my questions might seem a bit vague, so I can be a bit more descriptive about what I would like in my motor swap if needed. I've just been out of the Mustang world for far too long and it's going to need to come back slowly.

Thanks.

 

[nmcgrawj]

more compression = more power. If you arent gonna worry about power adders, i'd get the highest compression i could to still run on pump gas. Although its not as simple as the....static compression (i think its called) The cam controls the dynamic compression (again i think) which is also very important. Spending that kind of money i'd hook up with a Pro like Ed Curtis/Jay Allen/etc etc to get it built just the way u want.

 

[the boost creep]

more compression = more power. If you arent gonna worry about power adders, i'd get the highest compression i could to still run on pump gas. Although its not as simple as the....static compression (i think its called) The cam controls the dynamic compression (again i think) which is also very important. Spending that kind of money i'd hook up with a Pro like Ed Curtis/Jay Allen/etc etc to get it built just the way u want.

I was thinking high compression as well. Also, I am trying to buy a budget, but well-made longblock and CHP's motors caught my attention at around $5K. CHP has their dome-top piston PRO Street 331 with 12.30:1 compression. The main thing i want to make sure of is that this engine with such high compression isn't going to be tempermental for street use and with the 94-95 ECU. What would be the disadvantages of going with this motor with the dome-top pistons vs. flat top @ 10.30:1. Is the 12.30:1 going to require allot of tuning to even run correctly?

Thanks.

 

[Joe 5.0]

The edge of pump gas, generally speaking, is 11:1 compression.

12.3:1 would def be in race fuel territory.

I would stick with the 10.3:1, and also check out fordstrokers.com, I've heard alot of good about them.

 

[the boost creep]

The edge of pump gas, generally speaking, is 11:1 compression.

12.3:1 would def be in race fuel territory.

I would stick with the 10.3:1, and also check out fordstrokers.com, I've heard alot of good about them.

Gotcha. So it's looking more to me like the CHP PRO Street flat top @ 10.30:1. Joe 5.0, I checked out fordstrokers, but they don't advertise complete longblocks which is what I'm looking for. CHP longblocks seem to have good components as they give a complete breakdown of everything used. One thing I'm curious about is how theur PRO Street H/C setup is for power. It has AFR 185s and Comp 'Xtreme Energy' cam @ .544/.555 Lift and 216/224 duration. Does anyone think this setup will be tempermental with the 94-95 ECU or require lots of tuning?

Thanks.

 

[jromeo]

Gotcha. So it's looking more to me like the CHP PRO Street flat top @ 10.30:1. Joe 5.0, I checked out fordstrokers, but they don't advertise complete longblocks which is what I'm looking for. CHP longblocks seem to have good components as they give a complete breakdown of everything used. One thing I'm curious about is how theur PRO Street H/C setup is for power. It has AFR 185s and Comp 'Xtreme Energy' cam @ .544/.555 Lift and 216/224 duration. Does anyone think this setup will be tempermental with the 94-95 ECU or require lots of tuning?

Thanks.

I don't think that setup would be that tempermental at all. I had the 331 with the AFR 185's ,mine was like 10.1 . My cam was the step above the one your talking about, .555/.565 lift, I forget the duration. It got like 330 to the wheels with no tune. I would ask them about the stock valve springs on the AFR's ,I think max lift is at 550.I was told I should have upgraded them from day one. My valves floated at 6000 rpms. I'm in the middle of a fordstrokers 347 build right now and not knocking the comp cams , mine was good to me, but i'm going custom jay allen this time around.

 

[the boost creep]

Thanks for the reply jromeo. I'm pretty much set on the PRO Street 331 from CHP and I have asked them about the valve springs. Next, can someone look at the specs of this motor and tell me what u/l intake, oil pump, etc would be good for this setup?

http://www.coasthigh.com/product-p/10666-ps-f331-lb.htm

I have BBK LT headers that I plan to reuse. I would think for this motor, LT headers would be ideal, right?

Thanks.

 

[Joe 5.0]

Yeah, your headers will be fine. Might be a good idea to port match to the heads if the ports are way off. 1 3/4" primaries with a 3" collector would help, but the 1 5/8" will work ok.

Can I ask why not 347? You're just leaving hp/tq on the table with the 331. The 347 from CHP comes with a slightly bigger cam, a little more compression (still pump gas friendly), and is actually less $$$.

I'd say the 347 vs. 331 from CHP probably makes ~ 20rwhp more, and will have a broader tq curve.

JMO, either engine looks decent.

You also will want to check and see if the AFR's come with the valve upgrade or not, as AFR suggests better springs if you rev higher than 6000 rpm, which that engine definitely can.

 

[final5-0]

An all motor combo should be no prob for someone who knows how
to tune

If I was gonna go all motor ................

Yes ... I'd want the most compression
but
You say ... street motor ... so .......

you gotta be practical with pump gas and all

therefore

I'd consider the extra cubes of a 347 :Word:

Grady