[1980 TA]

I wanted to get some opinions on the intake for my combo.

Car is a 1980 TA with a 455 with 6x-8 heads. Howards cam with .560/.560 lift, 227/237 LS 112. Car is fed with a FITECH throttle body and spark is lit with an MSD controlled by the FITECH. Exhaust is factory logs that were smoothed and opened as much as I could feeding into 2.5 pypes system with crossover. Compression is 9.25:1.

Current intake is a performer with a 1 inch HVH spacer. From everything I have read a 1 inch spacer should not fit with the shaker but everything does.

Power goes through a tremec 5 speed to 3.08 gears.

Car runs good and I was happy with it until I bought the Lemans.

The Lemans has a 455 with a Howards cam with .530/.530 lift, 234/242 LS 109. Seems like a pretty similar cam. The Lemans does have 10:1 compression.

Lemans does have headers and the same 2.5 pypes exhaust.

The Lemans runs 3.55 gears with a TH 400.

The Lemans runs FITECH on a holley street dominator with a 1 inch 4 hole spacer.

I would have thought that the single plane HSD would have killed mileage but the Lemans is within 1 mpg of the TA around town. The lowend feels good on the lemans but not sure how much that is due to the torque convertor as the TA actually has more total gearing in first and second.

Where the Lemans feels so much different is in the mid range.

This got me thinking if the performer rpm or the crosswind from Butler would wake up the trans am. If the performer is a stock height and the northwind is 7/8 taller than stock, I should actually have 1/8 inch extra clearance.

I like the look of the northwind without the exhaust crossover and shouldn't need it with the FI. My one concern would be the cut down rear portion of the plenum as the FITECH opens the front and rear blades at the same time. I'm not sure how this would affect things compared to a carb.

Be glad to hear the experiences and opinions of others.

[25stevem]

Here’s what Edelbrock recommends for there intakes.
With the cam in your 455 in the TA you are above there stated usage of the performer.

[1980 TA]

Thanks for the chart. I hadn't seen that before. I thought the performer was a little small. With the square bore, a factory intake is not an option as I don't want to run adaptor plates.

[Scott65]

I don't think the cut down divider would cause any ill affects. But as long as the casting is decent, a competent welder could probably make the divider whole again. Just a thought. Any idea on the head flow? The Rpm is a great intake, but if heads don't flow much, it may actually hurt performance.
ETA: headers would most likely help a lot more than an intake change.

[Lee]

Stock unported heads and log manifolds? IMHO, the intake is going to make very little difference.

Here is some intake testing I did on my mild (8.3:1, unported heads) 455 with FAST XFI Sportsman efi.

The old P4B gave great average performance, and made the shaker fit better than the others, so I use it. The Performer test is a bit misleading - the throttle bracket slipped, costing it some peak HP.

The single planes all made a teeny bit more peak HP and slightly extended the power range, the dual planes made more midrange and peak TQ.

[Cliff R]

The cams are not that close and if you are evaluating power by the "seat of your pants" the higher compression engine with the larger cam on a 109LSA and single plane intake will "feel" a BUTT-LOAD stronger in the mid-range than the other.

The tight LSA crams the power into a much narrower RPM range and the single plane intake helps it work even better there. So when you are blasting up thru the gears the Lemans is going to feel much like throwing a small shot of nitrous at it from about 3000-5000rpm's.

The lower compression engine with the 112 LSA cam/dual plane intake will have a much smoother power curve and somewhat "boring" in contrast.

This is and has always been the problem with evaluating power without dyno and drag strip numbers. Without exception every single time I've tested a tight LSA cam and/or a single plane intake in a 455 built they "feel" much stronger than a wide LSA cam and dual plane intake. The outcome a the track has never in one single instance favored the tight LSA cam or the single plane intake.......FWIW.......

[ta man]

Originally Posted by 25stevem

Here’s what Edelbrock recommends for there intakes.
With the cam in your 455 in the TA you are above there stated usage of the performer.

Looks like a generic Chevy recommendation.

[ta man]

When thinking of intakes, spacers etc always include your air cleaner setup.
Sometimes working backwards from the best or stock air cleaner to finding an intake that works without fuss and keeps the most efficient or stock air cleaner assembly is best.
Also spreadbore on a spreadbore intake and squarebore on a squarebore intake is really making sense to me these days. It gets rid of adapters.

[Skip Fix]

"From everything I have read a 1 inch spacer should not fit with the shaker but everything does."
My 81 has a 400 6X-4s and a Performer. Swapped on a Shaker hood this summer and it is tight in front with a thick 1/4" Qjet gasket,lower in rear. Maybe the TB is shorter than a Qjet?

My 78 with an HO intake could fit a 1/2" spacer with a hybrid shorter '77 metal base but not plastic spacer between it and the scoop like the 77s had.

[1980 TA]

Cliff summed up the difference I'm feeling about perfectly. The other thing throwing off the "butt" dyno is probably the lack of noise on the TA as well. It is fully MLV on the floor, wheel wells and doors. It is crazy quiet for an old car. As Cliff put it, it feels boringly smooth.

The heads on the TA were done by Len Williams as part of his typical 455 build. Power is good to about 5000 rpms. The How to Build Max Performance Pontiac v8's lists the recipe as good for power through 5500 rpms.

I appreciate the wisdom of the group and it doesn't sound like an intake change is going to be worth the time and effort. Ram Air manifolds were a want when I built the car but I didn't have the budget for them at that time. Now it seems that finding a good reproduction is challenging.

The car won't see the track and spends most of the time below 3000 rpms and am trying to maximize the fun quotient.

[ta man]

Work on the timing that may give you all you want.

[Formula8]

Dual plane manifolds and TB injection systems sometimes do not play well together. There is an episode of engine masters where they ran into a problem with a Terminator on a Performer RPM LS. The RPM worked perfectly under a carb but the Terminator would not run cleanly until they installed a Vic Jr. For the most part, a single plane manifold is recommended for these applications.

[ta man]

Originally Posted by Formula8

Dual plane manifolds and TB injection systems sometimes do not play well together. There is an episode of engine masters where they ran into a problem with a Terminator on a Performer RPM LS. The RPM worked perfectly under a carb but the Terminator would not run cleanly until they installed a Vic Jr. For the most part, a single plane manifold is recommended for these applications.

Personally I would use a Torker 2.

[Formulas]

The play well part is erratic fuel distribution,
lean and rich cylinders
something you may not even notice on the average butt dyno but put a a/f sensor in every header tube and it shows up

dual plane intake FI. distribution can vary between makes and cubes but all you have to do is go single plane to eliminate those possibilities

honestly the performer should be used for mileage efforts there is simply nothing there for H/P performance

.

[Formula8]

Originally Posted by ta man

Personally I would use a Torker 2.

For this application, I would agree. That is what I run. For the EM episode, I don't think they make a Torker II for an LS so they went with the most comparable single plan which for that application was the Vic Jr.

[Skip Fix]

T2 has longer runners and a bigger plenum than the Holley/Tomahawk.