I just installed the acdelco rapidfire sparkplugs , and I have to say I am happy with the results . They certainly make a signifcant improvement ! " this LT4 350 just keeps on get'n better"...later

 

Those rapid fire plugs are great, the best ones you can get!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission

Current Mods: Edelbrock TES Headers, Hooker Cat-Back System, Performance Resource Chip, 160* Thermostat, Accel 8.8mm Ignition Wires, K&N high flow air filters, gutted air box, gutted MAF sensor, Throttle Body Coolant By-Pass, Homemade Ram-Air, Falken ZIEX Z-Rated Tires.

1/4 mile times without chip:
Best ET: 15.7 @ 89MPH
Best Corrected ET: 14.5 @ 96MPH

 

I swapped from old plugs to Bosch Platinums and saw a better idle & off-idle performance.

I then moved to Rapidfires from the Bosch plugs. At the time I was driving 110 miles a day to work. I saw no improvement in fuel mileage whatsoever. After 10,000 miles, the splines on the Rapidfires had burned off, and they looked like regular plugs again. I swapped in my old Bosch platinums which were in the top of my tool box, and gained 1 MPG on the highway. Since I was averaging 600 miles a week on the T/A, I believe the MPG figures. I used a running average across the last five tanks to calculate it.

The point of all this is that any time you replace a worn spark plug with a new one, you'll see a performance improvement. I think the Bosch Platinum is superior for durability, however. That's probably why TPIS uses them in all their projects as well!

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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines,
5-point racing harness, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Speed-sensitive steering conversion, underdrive pulleys, Crane Hi-6 & more. 1.05g skidpad verified.

 

I've installed the AC Delcos, and I like them as well.

 

Lt4 350? What happened to the twin turbo 400?


this guy is full of more S*** than a broken toilet at a chevron station

 

Big improvement over the old plugs? If the old plugs were worn out or defective then any plug is an improvement. Pull the rapidfires and install similar AC plain jane plugs R43TS for example. If results are poor then I'll agree that the rapidfires are an improvement. If not, then the extra cost of the rapidfires isn't worth it. I run ordinary AC plugs in everything including my race car and they work fine. Platinum plugs will just last a little longer before they burn off or wear out. Regular plugs are cheap. Change them often and performance will never degrade.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
Best ET on a time slip: 11.857
Best corrected ET: 11.233
Best MPH on a time slip: 117.87
Best corrected MPH: 125.46
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!

Member of the Calgary Drag Racing Association

 

Hey , pablo , I don't know if you were around when I did the switch , but it was made my friend is driveing around with the small 400 , he also go me a deal on a new LT4 350 so.......why don't you take a look at the past boards ---I did it about 3-4 weeks ago . OR! if you are ever in Lake George N.Y ( in the summer) and you happen to pull up to my car at a stop light , and while you are at the stop light when you see green --look for my car-----where is it? it is gone--left your car in the dust , all because you underestimated mine . Oh I also have the garret air stage 3 turbos from before . The whole point here is QUIT F***ING DISSING MY CAR ! just because I would rather spend money on my car than get a dam scaner is totaly up to me ! Yes , I would like everyone to see my pride and joy , but if nobody sees it , why the hell should I care what they think . So.... say what you will , only when the day comes , will you understand what kind of ponys lurk within this camaro .....later

 

So, what kind of manifold did you use on your LT4?

 

didn't I allready tell everyone that I am using the smallblock ACCELL pro-ram multiport 1,200 cfm EFI system , you buy it through lingenfelter , but at the time I cose Next Generation by YearOne , the 400ci was still a smallblock - same application. Only difference is that I lost a little throtle response when swithcing from 400 to 350 ( GEE WONDER WHY ) . It is not terrible , I most deafenatly plan on installing a cam with more duration and mabie a little more lift to solve this problem though . ......later

 

I see...
So what did you do about the coolant passage differences between the LT4 and the SBC?

 

me thinketh that he old plugs were shot.

 

I replaced my old standard AC plugs with new standard AC plugs a while back. My old 82 idled better and I got improved throttle response with the new plugs. Worn plugs to new plugs will gain improvements regardless of brand. The rest is just gimmicks. V-power, u-groove, rapid-fire, split fire, bosch platnum +4, etc...


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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

I have had no problems w/ the cooling system , so far....Are you aware that the water pump is driven off of the cam ? It is still a small BLOCK . Unless my father did something behind my back , BUT , I doubt that ( he helped me install it ) ....later

 

Well, thats really interesting. The LT4 has an entirely different cooling setup, its reverse flow. The LT4 engines are like the LT1, there are no coolant passages in the intake, meaning there is no provision on the heads for coolant to go into the intake either. I also just noticed the intake bolt pattern is different too. Obviously something was changed... or... you dont have that engine in your car. I think I'll just step out of here now before I need to get my wading boots.

[This message has been edited by madmax (edited July 31, 2000).]

 

hey , I know I have been telling everyone I have the LT4 , But madmax has just made something perfectly clear , I can understand what all the confusion is about . See when madmax told me about the cooling system deal---I stoped to think .... LT4.....all this time I have been talking about the LT4 when in fact it is the ZZ4 engine ---now this should make some sense to you all , back when I told you about my engine switch I told you I had bought the engine(350) for around $3,000 . I wish someone would have just brought up the fact that the LT4 is WAY more expensive and the deal must have been bogus---Because then I would have corrected my spelling error , right then and there .BUT instead I kept spelling LT4 ....when in fact it ZZ4...hope this clears this whole damn mess up .later --thanx madmax---hope I can still enjoy the great whealth of knowledge this site has to offer ..Please don't shut my ?'s out just because I made this damn mistake .