Desktop Dyno anyone? 327 Small Journal in a '68 Fastback mustang!

Discussion in 'Engine Topic' started by Seths327Fastback, Feb 12, 2020 at 8:15 AM.

  1. Seths327Fastback

    Seths327Fastback New Member

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    Some of y'all are going to hate me, some of y'all 'll love me.
    My name is Seth and I am new to the forum, I live in North Carolina and am a sophomore high school. I love cars and am currently in the process of stripping down an old '63 Small Journal 327 SB Chevy. I am a Chevy guy but, a friend of a friend of mine is going to sell me a '68 Fastback Mustang without a motor or transmission this summer when I have the money. It's an originally 302 4-speed car with a 9" rear end. Its black (was originally red), manual brakes, manual steering, and can be put back together with this SBC while I'm in high school. I originally wanted a Chevy (El Camino!) or camaro. But this mustang is to good to pass up (or to be true). Can someone run this motor through a desktop dyno? Again i'm a highschooler and cant afford the program.

    327 Small Journal SBC
    64cc Vortec Heads
    -170cc Intake
    -1.940 Intake Valves, 1.500 Exhaust
    -stainless steel valves
    -Beehive Springs for up to .550 lift
    -1.5 stainless steel full roller rockers on 7/16 screw in studs
    -Performance hardened push rods
    -9.75 Compression Ratio
    -Stock Forged Crank
    -Stock Forged Rods
    -Forged aluminum flat top pistons 2v-relief
    -Custom professionally dyno tuned Quadra-Jet Carburetor.
    -Electric water pump, no power steering or brakes
    -Comp Cams Solid Flat Tappet 230/236
    -268 intake duration, 274 Exhaust duration
    -intake lift .488 with 1.5 rockers,
    -exhaust lift .501 with 1.5 rockers
    -110 LSA

    Any other specs I need to include for results?
    I am going to run splayed 4-bolt main caps and a crank girdle, along with rocker girdles. But I don't think the desktop dyno cares.
    They make a kit to convert center bolt heads to accept classic perimeter bolt valve covers and give enough clearance for girdles.

    The car is a 1968 Mustang Fastback with manual brakes and steering, no A/C. I want a 22 gallon gas tank kit. I am aiming for 2800-LBs with gas and my 140lb self I am going to upgrade the suspension with HD coils and leaf springs but leave it stock style. Koni or bilstein shocks, stock height. I will convert the front brakes to disk with summit parts and leave the rear drums. Putting the biggest/widest tires possible on stock height. T-56 off an LS1 with 4.11 Posi rear gears with 27" rear tires. I think the car will be nicely set up for everything. What do y'all think? I probably left some stuff out. I hope I wont be torn up for "wasting" a chevy motor in a ford but thats the only way to fix a ford! Inspiration is coming from a good friend with a 327 Chevy in a '40 ford coupe with a t56 and 4.11 gears and a towing cam. : ) Thanks in advance to anyone putting my build through the desktop dyno.
     
  2. tom3

    tom3 Veteran Member

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    No dyno program but I'd look at 340 to 350 HP all dialed in. As long as the cam lasts anyway. I'd cut the lift and add a bit of duration for cam life and to match up with the vortecs a bit better. But that's just me.
     
  3. Rdobbs1977

    Rdobbs1977 Huge Guns N Roses Fan

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    I like the fastbacks and gm motors. couple things that jumped for me: splayed going to cost you some coin on the machine work plus cost of splayed caps unless your block is already set up like this and you got the caps. Crank Girdle? No offense but lmao---man that aint nothing but SNAKE OIL, don't bother spending i dunno $100 bucks on it. don't know what flow rates/max lift rates are on the heads and don't like the valve sizes. 2.02 way to go for an SBC imo. I run an elec water pump on my drag car but would not run one on a street car. Elec pump is only gonna give you maybe 5 extra hp. Running a clutch fan is a bit more 'bullet proof.'
     
  4. RS1979

    RS1979 Veteran Member Lifetime Gold Member

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    I agree with Tom on the HP but unless you're running a high HP or a high RPM engine you really won't need splayed mains. I ran a 327 years ago that put out well over 400HP and I used a 2-bolt block. It saw 6000-7000 rpms frequently with no issues.
     
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  5. badazz81z28

    badazz81z28 Veteran Member

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    What heads did you run? With the OPs Vortec heads and cam combination...I would not expect "well over 400hp". I ran a similar combo with ported vortec heads, roller cam on a 350 and it Dyno'd at 420hp with a good Holley carb and a air-gap intake. Red-line was about 6000 rpms.

    Best advice to give is to replicate power proven combos...Personally I rather have a 5.0 Ford engine...they just sound cool and fitting to a mustang.
     
  6. RS1979

    RS1979 Veteran Member Lifetime Gold Member

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    I wasn't talking about his engine. I was talking about mine. The heads I had on it were Sportsman II. I was talking about his getting splayed mains. It was an 11:1 with a 300-36 intake and a 3310 750cfm Holley. I also had a 100 shot on top of it.
     
  7. badazz81z28

    badazz81z28 Veteran Member

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    No, I was just more curious about the heads you ran.
     
  8. Seths327Fastback

    Seths327Fastback New Member

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    Alright, so scratch the silly crank girdle, and the electric water pump. Just a kid, so I thought the electric water pump would free up power, I read crank girdles provided a little stability. I am aiming for 400 HP and 390 Torque with decent fuel economy. This was the cam recommended to me by COMP Cams. I have heard of 327s running to 8000 reliably but I would set the limited to 7100. I am friends with the owner of a machine shop so modding the heads for screw-in studs and the block to accept splayed 4 bolts is not a problem. I am trying to make this a rock solid base that can be rebuilt multiple times in the future. From what I've gathered off the forums the 170cc ports of the vortex heads mach up perfectly for a street rod 327 and are the iron/budget head of choice for many 327 engines. Forgot to mention RPM air-gap intake (dual plane). I ahem heard there is little to no gain off of putting a vortex head above .500 lift and/or porting them. Bigger valves don't help either. I read on HOTROD magazine that they spent 14 hours porting a vortex for 16hp and less bottom end! The split duration cams seem effective on vortex heads because of the small exhaust ports. Thank you all for the info and I hope to learn a lot from this forum.
     
  9. G72Zed

    G72Zed Veteran Member

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    Rdobbs1977 is right on that crank girdle and the elec. water pump, listen to him on that. I have built quite a few 327's and have been using/racing one since 1988, been through many builds like this. My guess was in the 375hp range because of those heads, even if they have small valves, as long as it's build well with proper machining.

    All 327 be it SJ (62-67) or LJ in 68/69 are all 2 bolt mains.

    I made 355HP at the wheels (415HP FW) with a basic 327, and 465hp at the wheels (525hp FW) with 150 shot, my Camaro ran 12.70 @ 110 and 11.1 @ 119.5 with the NOS, and all this with a 2 bolt main and original CAST crank, but on tear down after 2 seasons and 20+ bottles I was getting "cap walk" and radial lines on the crank, so upgraded to splayed billet and a LJ OEM Vette forged crank. Used the original 1968 291 camel humps, ported them myself and stayed with the 1.94's. 650 Holley, 1970 z/28 intake with 1-5/5 hookers.

    If your goal is NA at the 375-400HP level, save your coin on the splayed (for now). Nice build, lots of experience here.

    By the way, I tossed your info into the DTD for you. I was very close LOL

    pic2.jpg
     
  10. Seths327Fastback

    Seths327Fastback New Member

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    I know these DTD's are scary accurate/close from what I've seen on other forums, and your guess was spot on :D
    I'm a little disappointed on the torque side, vortecs are supposed to keep low rpm velocity high, and I'm disappointed at the top end, I thought the solid lifter would help there. Thats as big of a cam as I thought would work well with vortecs. I saw vortec headed 327s run 400 hp on other builds, what am I missing?

    We ran the numbers on the block and although the motor came out of a school bus (we were told), the motor came back as a corvette forged crank, high nickel content block, and forged steel rods. It had really crappy dished pistons and low compression, open chamber truck heads on it. We ran the head numbers and couldn't find anything on them. Motor had never been torn down and had no ridge at the top of the cylinders, however it was sitting on the ground for 10-15 years and is going to be boiled soon and we are going to get the crank balanced and the rods checked for cracks (can you balance rods?).

    This is still a street build that I would have to be able to afford to drive on cheap gas. Would bumping up to 10:1 compression help? My friend insists on it. Says 9.75 won't do. Cap walk is my worst fear with me wanting to turn up the RPMs, I don't plan on nitrous so thats one less thing to worry about.
     

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