FlatBlackZ28

Which spark plugs would you guys recommend for my 21* heads and nitrous?

I will be running 11.2-1 compression. The engine will regularly see a 100-150rwhp shot of nitrous at the track and occasionally on the street.

Any advice is much appreciated.

quik95lt1

iTrader: (7)

ngk br7ef I believe is what you want id start there worst case its too cold and you go back to a tr6

lt1slowz28

I am using ngk tr6 seem to be a lazy mans one size fits all kind of plug. Cheap too.


You aren't running much compression or nitrous.. one heat range or two colder should be fine depending on timing.

Purple Poncho

iTrader: (1)

Don't forget you need a 3/4 reach gasketed plug so the TR6 won't work.

FlatBlackZ28

I ran the TR6 in my last engine and I believe my compression was about the same. Never ended up spraying nitrous but the TR6 wasn't too cold. Just order the BR7's from Summit. I have to custom fab some spark plug wires. Should be ok for N/A, I'm hoping

Purple Poncho

iTrader: (1)

That is fine on stock heads with the shorter reach and tapered plugs but your new trick flows and most all aftermarket heads use a 3/4 reach gasketed plug. Something like an NGK BKR6E or an autolite AR 3923.

FlatBlackZ28

****, I didn't even think about that. What plug should I use for good N/A performance and the occasional 100-150 shot on my Trickflows?

lt1slowz28

start safe with the 7's read the plug after a nitrous pass and adjust accordingly.

FlatBlackZ28

Found out I can't even use the TR6's or the next step colder with my heads. I ended up going with a 9, R5672A-9 is the part number. with 11.0-1 compression, the recommended plug for my head has a heat range of 8. I'll be running 11.1-1 or 11.2-1 compression plus nitrous, so I went with the next step colder. It's a 9, but not on the same scale as plugs for stock heads.

TravisMcGill2000

iTrader: (2)

Im running 5671a-7 in my motor. Its 12 to 1 compression.

TravisMcGill2000

iTrader: (2)

Flatblack why didnt u shoot closer to 12 compression

FlatBlackZ28

The heads are already shaved down to 53cc chambers. I'm using a .040 MLS gasket, 5cc valve reliefs and my block is stock deck height. Not too much I could really change. Needed the valve reliefs for the larger valves, didn't want to go with a domed piston. Also didn't want to shave the heads down anymore than that incase they ever needed to be shaved again due to a rebuild or damage. What else could I do? Or am I calculating it wrong?

Bore: 4.020
Stroke: 3.48
Rod Length: 5.7
Gasket bore: 4.040
Head CC: 53
Piston relief: 5
Deck height: Stock

TravisMcGill2000

iTrader: (2)

If your running stock deck height then run thinner head gaskets. Run a .029 gm gasket. That jump ur compression up. Im running those gaskets.

FlatBlackZ28

I prefer to run a MLS gasket. I was checking summit for gaskets for a 97 block and the thinnest MLS gasket I found was .040. it looks to only change my compression ratio from 11.2 to 11.49 which isn't a huge amount. I'm not too worried about a couple tenths of a compression point. I want this to be as reliable as possible and run nice and cool. I already have a set of trickflow MLS gaskets that ran me about $140 shipped for the pair. I don't have a problem with 11.2, it's almost a full point higher than the stock 10.4.

TravisMcGill2000

iTrader: (2)

If you didnt already have gaskets. You could go with cometic. They will make them any thinkness. Cant wait to here your results good luck.

FlatBlackZ28

Thanks Travis! I'll keep you posted. We are hopefully installing the engine into the vehicle within the next 2 weeks. Still have to run all new vacuum lines and custom make my plug wires for my coil conversion. Other than that, I just have to hope I didn't lose any bolts for all my accessories and such. Everything else seems to be ready to go. Just got my new ATI crank hub and bolts today.

TravisMcGill2000

iTrader: (2)

Thats great. I should be finishin mine up by the wnd of april myself. Then be ready for the shootout.