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Topic: Switched from GT40 intake to Performer RPM intake.... (Read 8721 times) previous topic - next topic

Switched from GT40 intake to Performer RPM intake....

Yesterday I switched from a GT40 intake to a Performer RPM intake (the original not the RPM II) in my Thunderbird. After checking for leaks, checking engine vacuum (17 inches like before the swap), and setting the base timing to 16* BTDC I took the car out for a drive. I have heard from multiple sources that this swap would be a bad idea. The intake doesn't match the operating range of the cam, the intake is too big for my setup, the intake will make the engine lose low end torque, the GT40 is better for my car because of it's weight (car is 3700lbs+ with driver). Well they were all wrong :D. Driving around at low throttle the car acts just like it did with the GT40. No bucking, plenty of torque off the line to get the car moving, no low end loss, etc. Start jamming on the throttle and the fun begins :burnout:. The engine revs noticeably quicker than it did before. Half throttle from a stop still results in massive wheel spin and the car going sideways like it did with the GT40 but it takes longer for the tires to grab. 1/2 throttle to WOT between 20-40mph results in wheel spin, which with the GT40 requires temps below 50*. The car feels much more spoogey than it did with the GT40 intake. When the weather cools off I'll take it to the track and report back. It feels like the car might pick up 1-2 tenths and 1-2mph from this swap.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Switched from GT40 intake to Performer RPM intake....

Reply #1 –
I think if someone where to put that intake on stock heads it would suffer but definably not with matching heads. im gathering parts for mine to go from e7 and explorer intake to trick flow street heat intake and twisted wedge track heat heads. my motor has a b303 in and ill probably end up doing 1.7 rr.. im curious as to the intake is a idle-5500 range and the cam is 2500-6500 hopefuly its a decent combo

Switched from GT40 intake to Performer RPM intake....

Reply #2 –
I wonder about the difference between your new intake, and my tubular GT-40 with the TMoss ported lower. The ports were matched to the Trick Flow heads, and were opened up from top to bottom. I use a 70mm throttle body on mine.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #3 –
.........and where are the pics? You know the rules!!!!! LOL.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #4 –
Quote from: 87tbird5.0;448717
I think if someone where to put that intake on stock heads it would suffer but definably not with matching heads. im gathering parts for mine to go from e7 and explorer intake to trick flow street heat intake and twisted wedge track heat heads. my motor has a b303 in and ill probably end up doing 1.7 rr.. im curious as to the intake is a idle-5500 range and the cam is 2500-6500 hopefuly its a decent combo


It's not only heads and cam operating range but gearing as well. With a 2800rpm stall converter and 3.73 gears I want max torque/horsepower to be in the 3000-6000rpm range and also average power there as well. The RPM intake should do that better than the GT40, but track times will have to prove that out. I plan on going to the track to test it out the next time the track is open and it's below 70* outside. Which may not be for a couple of months.

Quote from: vinnietbird;448720
I wonder about the difference between your new intake, and my tubular GT-40 with the TMoss ported lower. The ports were matched to the Trick Flow heads, and were opened up from top to bottom. I use a 70mm throttle body on mine.


You may pick up something with a Holley Systemax. However your cam was designed with a GT40 intake in mind. The GT40 isn't restricting your heads (the GT40 on mine was as it wasn't ported). I though about getting a GT40 lower ported for mine but the cost of another lower + porting was within ~$35 of what I paid for the Performer RPM.

Quote from: vinnietbird;448721
.........and where are the pics? You know the rules!!!!! LOL.


I've got some py cell phone pictures. Underhood is still a bit dirty from the swap (I also nicked some paint on the A/C lines). The only thing that bugs me about the new intake is it sits closer to the back of the distributor so I can't get the distributor boot to fit.

Before:




After:



88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Switched from GT40 intake to Performer RPM intake....

Reply #5 –
I will check the pics this evening. I'm at work, and the computers we have won't show pictures on the forum. Good point about my cam and intake. As it sits, the cam was designed for the engine exactly as it sits. I'm ready to step away from working on it. I can focus on cleaning, setailing, and other things now.

There has to be a way to get your distributor boot on. I'd hate for mine not to be there. Are you going to paint your upper intake (asking this question because I can't see pics til this evening)? If so, is it feasable to remove a small amount of material from it to allow the boot to fit, then paint it?
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #6 –
It's already painted. And not Ford blue ;)
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Switched from GT40 intake to Performer RPM intake....

Reply #7 –
When I had the Trick Flow intake on mine a couple of years ago, I had the same issue. I trimmed the bottom of the back of the boot just enough to allow the boot to fit. It washiznitting where the upper and lower went together.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #8 –
Cell picks look great. Why are you talking to vinnie about intakes!!lol.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Switched from GT40 intake to Performer RPM intake....

Reply #9 –
You have the non lock up trans yet?
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Switched from GT40 intake to Performer RPM intake....

Reply #10 –
Kitz? Really? LOL. LOL. Yeah, I've been though two or three intakes and a couple of sets o valve covers, but those days are done. THAT's why I got the custom cam. Kinda locks me into what I have. LOL.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #11 –
Looks sharp Lou...nice work. From the sound of things, you'll definitely pick up a tenth at least..

X2 on Vinnie and intake swappin....what are yous doing? Having a swap contest? LOL
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

Switched from GT40 intake to Performer RPM intake....

Reply #12 –
I'm done...I'm REALLY done. LOL
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Switched from GT40 intake to Performer RPM intake....

Reply #13 –
Quote from: Kitz Kat;448745
You have the non lock up trans yet?

Yep. 2800 stall non-lockup PI Stallion converter.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Switched from GT40 intake to Performer RPM intake....

Reply #14 –
that is a jaw dropping engine bay!!!! very nice work looks factory. clean not butchered