Sidewinder or Police Interceptor ???

[wicked fast]

Which intake will work best on a mild (9.5-1) 428 with Medium riser heads ????

Cheers,
Bill Cook

[wtcobra]

Blue Thunder.

wt

[427sharpe]

Of the 2 choices, the PI. The sidewinders were a higher rpm application. You may find that the PI is a bit restrictive if your motor will see any rpm though....

[wtcobra]

The Blue Thunder is an improved version of the P.I.. The P.I. is an aluminum version of the iron Cobra Jet intake. The Sidewinder is not a high rpm manifold, good to about 6200, but does have good mid range response. If you have to buy the intake, get the B.T., hands down the best and better than the Performer RPM, Sidewinder, or the P.I. , even assuming they will fit your heads. The Sidewinder was made for the MR heads but many have been modified to fit the Low Riser and/or the Cobra Jet heads. The P.I. was for L.R. and C.J. type heads, not M.R. heads. The B.T. is available for M.R. heads.

wt

[A Snake]

I'm unaware of Sidewinders being modified to fit CJ and LR heads as such, but the ports are ok. They look shorter, and are, but look at the bottom of the intake runners. They're higher and the top is in the same place.

What won't work at all is MR heads on a 428. Remember, a 428 is a big overbore from a 390. A 427 is a different block with a much larger bore. The MR valves are SPACED FARTHER APART and they're much larger. The valves will hit the top of your block on a 428 and as I am told, you can not cut enough relief for them to clear without hitting water.

I suggest having a well preped. set of CJ heads done and try the Sidewinder with that. I've done it and it worked very well. Do remember the long stroke of the 428 is not intended for the high rpm a 427 is. Unless you're just going to drag race, trying to make a 428 buzz like a 427 is a waste of time. It makes plenty of HP and torque up to about 5500rpm.....plenty enough to give you the ride of your life.

The police interceptor manifold was the same as the CJ and will work fine. It won't work as well "upstairs" as the Sidewinder, but hey, how much is enough.

One good thing is that the Sidewinder looks right under the hood.....with a pair of plain chrome valve covers, you can't tell the top end from a 427.

[Chaplin]

WTCobra- Why is the Sidewinder better than the performer rpm?

I assume the Sidewinder works with Edelbrock aluminum heads??

Also, where can you buy a Sidewinder?

Thanks,
Mike

[a427sc]

WT How about the Victor? Anything new to report since the last thread? What about a worked over PI with a cut down plenum, and 1" spacer, your opinion? What did you do to the BT to make it better? Inquiring (nosey) mind need to know.

Don

[wtcobra]

Don-just got back from R & G, and tried out the Victor along with 2 other cars and I must say that I am favorably impressed with the Victor. It makes terrific low end torque and will still wail upstairs. Took mine to 7500, and no problems. Ran a 10.30 on the drag strip and had to get out of it every time I shifted just to stay in my lane. It is a very good manifold as the other cars also ran their best times with the Victor. Just make sure you supply it with enough gas as Holley Blues and Mallory 140's are not big enough if you are over 450 horses.

Chaplin-The Sidewinder and Performer RPM, both ported, are about the same. I said the Blue Thunder was better, and I say that from testing them on engines. The Sidewinders are original manifolds, so you can find them at SAAC events or other events. The SAAC newsletter usually has one for sale.

Wayne Turpin

[Chaplin]

WTCobra-
Why is the Blue Thunder better? More horsepower, broader torque curve, etc.? What rpm range is the Blue Thunder designed to run in? Where does it make its peak power/torque?

I'm going to be driving on the street exclusively, and I doubt I'll ever see 6000 rpm. Sidewinder or Blue Thunder??

And insight would be appreciated.

Thanks,
Mike

[wtcobra]

Chaplin-given that you are going to drive yours only on the street, and less than 6 grand, then the Sidewinder, Performer RPM, or the B.T. would work just fine on your car, and unported you probably could not tell the difference. If you are looking for performance, among the dual planes the B.T. allows for better flow at higher rpm if properly ported without affecting low end torque, but you have to have the cam and heads to realize the maximum gain from reworking the intake.

Wayne

[concobra]

To wtcobra

I find your comments on the blue thunder verses the peformer RPM very interesting and would like to further this dialog.

I went the direction of the performer RPM. I write this to identify where I am coming from for future dialog. I do not wish to present the image that I am defending my choice. I just wish to increase my knowledge base.

My choice for the RPM was based on investigation of dyno information supplied to my by a nationally recognized FE engine building company. (I cannot mention their name because I do not have their permission to do so. But I'm sure that you would know who they are if I would.) In their testing they found both the RPM and blue thunder to be equivalent to each other with a slight torqued advantage going to the RPM. This advantage is so small that any engine changes could easily effected this. Based on this information I went with the RPM as it seemed to be a good starting platform, easily available and less money than the blue thunder.

After dynoing the motor with the RPM we observed the that RPM does what Edelbrock claims. Good mid range, throttle response, good cylinder filling capabilities through the mid range. I attribute this to a good runner design. It did fall short on the top and I attribute this to plenum volume being quite small.

In looking at the Blue thunder it seems to use some of the normal runner length to create extra plenum area and may be able to continue to pull higher power readings on top. The shortfall being not as strong a signal in midrange and therefore softer on power there than the RPM.

Since the motor spends most of it's time between 2500 and 5500 RPM I felt the performer would be best. Since the top end charge, 5500 to 6000 occurs very quickly and will not advance the car that much faster.

What do you think?

[wtcobra]

Phil-Concobra- I think the way you are using your car, the Performer RPM is a great choice and particularly if you are happy with it. My remarks regarding BT intakes were predicated on all out performance engines with fully ported and matched heads and intakes. A RPM or BT intake is a fine selection for useage you have described, and any differences would not be noticeable in my opinion. You should have come to R & G as there were 7 Contemporary cars there, all with 427 FE's. Next year maybe we will have a reunion for all Contemporary cars

Wayne Turpin

[Tom Kirkham]

Something to consider is that the B.T, sidewinder, and the MR intake have the oil fill provision in the manifold. The CJ maniflold is an iron version of the PI manifold. The BT is a very slightly tweaked version of the MR. For visual reasons I prefer the BT. My car has a RPM. Also the the RPM manifold does not have PCV valve hole machined in (the boss is their) which is used for the oil return line from the puke tank. My $0.02

[My427stang]

I have run all those manifolds, RPM, F427, Alum PI, and sidewinder. They are within 1-2 horse of each other and any of them IMO would be undetectable from the other if you didnt know it was swapped.

If it were me I'd use this priority

1. Performer RPM (because its new and easy to find)
2. Edelbrock F427 (old, but pretty darn close to the RPM, no cheaper usually)
3. 428 PI Great intake but worth bucks to collectors, better to use new tech for same or cheaper with RPM, plus exh crossovers frequently rot out
4. Sidewinder - Another great intake but offset carb makes for a PIA most of the time, plus weirdness brings big dollars LOL


With those above, like I said, I'd bet a dollar you couldnt tell a difference with any other changes. Save the PI and sidewinders for the guys who want them, buy a new RPM and off you go, or buy a used F427 in nice shape and run right along side the RPM's