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#1
01-23-2012, 05:10 PM
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Swapped Performer for Performer RPM, now swap back?
Last spring I put a Performer RPM on the '68 400 in my '80 TA. After the swap, the car seemed to pull a bit harder higher up, which I expected. I know there were also sealing issues as the front of the old Performer by the heads was becoming more and more carbon stained as time went on, thanks to old thin intake gaskets not properly sealing. I'm sure that didn't help performance any.
When I swapped the intake, I also swapped the water pump. Long story short, I'll be swapping the water pump again this spring (thanks, cheaply made parts store junk). While I have the coolant drained, I'm wondering if I should swap back to the Performer or keep the RPM. I don't know much about the motor internals. It is a '68 YA 400, '69 #62 heads, Holley 3310 carb, stock ratio rockers, unknown cam (I'm guessing it is stock-ish as there is no noticeable lope at idle and the car runs out of breath after 5,000 RPMs). 3.42 rear gear, TH400 trans. Motor may be 30 over (I know it has been rebuilt at least once as there is a motor rebuilder metal tag riveted near the driver's side motor mount). Car has Hedman headers and 2.5" dual exhausts through Flowmasters. Since the early block is in the later car, it has motor mount adapters. I would keep the RPM, but found that even with a WFO drop base, everything still sits about .5 to .75 inches too high to run a shaker (as well as sitting slightly towards the passenger's side, which could be remedied by re-riviting the lower portion of the shaker to the fiberglass scoop slightly offset). Not sure if the current motor mount adapters available are any different and center everything or not. Since I can't run a shaker with the RPM, but could get creative with the WFO base pan, carb spacers and offsetting the scoop base plate to make everything work, I'm wondering which intake manifold to run. What is best for performance for my somewhat unknown combination? I'd give up the ability to run a shaker with this combo for more power if it is worth it, but if we're talking a small gain only noticeable on a dyno, then I'd be inclined to put the Performer back on (with fabbed shaker) until something lets go and I redo the motor. Thanks for bearing with this long rambling post by the way. 
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Like Father, Like Son. Dad's car: 1977 Trans Am: Original Owner, T/A 6.6 400, modified TH350, Hooker Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.91 rear end My car: 1980 Trans Am: 1968 400, 1969 #62 heads, TH400, Hedman Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.42 rear end |
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#2
01-23-2012, 08:13 PM
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It sounds like your combo is not set up to take full advantage of the RPM intake. It may perform as well or better with the Performer intake at least in the off-idle to 5000 rpm range. If the car doesn't see any, or not much track time, and no other changes are planned to match the RPM intake, I would use the Performer. With some head porting and a more aggressive cam the RPM would be the choice.
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69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car. 79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads, Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.68 @ 126 so far... no tuning yet. |
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#3
01-23-2012, 08:55 PM
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That's what I was figuring. I have to heli-coil one of the carb stud holes in the Performer as a previous owner over-torqued and stripped the threads, but that's about the only issue with it (aside from it being really ugly and needing cleaning up). I figured for ease of swapping (when I did the water pump last time) I may as well put the RPM on it so I have one of each intake on hand. In retrospect I should have tore it down, reworked the Performer, and then reinstalled.
Eventually since I have fairly desirable heads, I'll put a cam in the car and match everything. At that time I'll also throw on the RPM. Thanks for the advice. I appreciate it.
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Like Father, Like Son. Dad's car: 1977 Trans Am: Original Owner, T/A 6.6 400, modified TH350, Hooker Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.91 rear end My car: 1980 Trans Am: 1968 400, 1969 #62 heads, TH400, Hedman Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.42 rear end |
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#4
01-24-2012, 08:06 AM
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I would heli-coil all the bolt holes, and use hardened studs in lieu of bolts. They few extra minutes work is well worth it, especially when you have it all in place and tightening the last carb bolt and it strips out the threads!
The RPM brings nothing to the table at your power level, at least not enough to deal with nothing fitting like it should.......Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#5
01-24-2012, 11:16 AM
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Thanks, Cliff! Will set the RPM aside for whenever the motor gets redone and clean up the Performer. Will also heli-coil all the carb stud holes, not just the damaged one. Be interesting to finally get a shaker on the car!
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Like Father, Like Son. Dad's car: 1977 Trans Am: Original Owner, T/A 6.6 400, modified TH350, Hooker Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.91 rear end My car: 1980 Trans Am: 1968 400, 1969 #62 heads, TH400, Hedman Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.42 rear end |
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#6
01-24-2012, 09:29 PM
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Quote:
Don't forget when running a square bore carb like the Holley you need the flat metal plate adapter. Not the 1" adapter just the .063" metal plate that helps seal the carb on the thin opening of the larger secondary openings of the spreadbore carb flange. $5.95 JD
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Good luck to the new owner of the Ventura II! Sold the car after 13+ years. Look for it on the Hot Rod Power Tour in the future as it's currently being re-configured as a Pro-Touring ride! 
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#7
01-27-2012, 11:01 AM
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Quote:
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Like Father, Like Son. Dad's car: 1977 Trans Am: Original Owner, T/A 6.6 400, modified TH350, Hooker Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.91 rear end My car: 1980 Trans Am: 1968 400, 1969 #62 heads, TH400, Hedman Headers, Flowmasters, Edelbrock Performer Intake, Holley 750 cfm carb, 3.42 rear end |
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