What plugs for Angle heads n hi compression

Hi People,

Just about to have amotor shipped out of LA to the UK and just sorting out my last summit order and need some help

The heads on the motor are 69 or 70 LT1 angle plug heads and I need to know what plugs these use so I can order some up, can any one help with a part number?

The motor's been set for 12.5:1 compression so some advice on heat ranges would be handy also.

Cheers

Gotzy

 

Production 70 LT1s didn't come with angle plug heads. Do you have a casting number?
Larry T

 

Yeah sorry it's late, motor is a LT1 fitted with angle plug heads, I think they were 70 492's

Steve

 

I had those heads on my lt1 and i ran accel header plugs. I wish I could remember the number but I just used the ones listed for a 70 corvette or camaro. That is a awesome motor mine had 11:1 a torker intake 780 holley D.P and a solid 550 Lift cam.

 

If it has angle plugs (492, 292, or bowtie) it 5/8" tapered seat plugs. That's a T suffix. If you have enough room in the chamber you can use an extended tip plug (add S to suffix).
If it's strictly drag racing you might try a R42TS AC plug. If it's a track engine go a little hotter, like R43TS. If your gonna try to run it on the street, I'd try R43TS or maybe R44TS if you have a fouling problem.
If you're gonna run a MSD box, the R43TS will probably work on the street without fouling.

And to confuse things even more, the old Chevrolet Power Manual (EXCELLENT reference material) recommends 441TS, 443TS, or R42TS for Drag Racing and 436TS or 438TS for Track Racing.
Larry T

 

My set in the shop has bl-11y champions,they are tapered seat plugs so ngk ur4 or ur 5's should work thats what ill use in these once i get them bolted on.Cold plugs with high compression.Ran the champions on my 327 engine back in 1989 with 13.5 compression and a weiand tunnel ram worked very well but now days id lean toward ngk's.

 

Cheers Guys, I think I'll re read this in the morning, lots to digest there

It's a strip only motor, it's an un used race motor I found on Caigs list and got my mate in LA to pickup for me. They are angle plugs heads and have been fully ported, motors got hand finished pistons, 660 lift roller cam and bits. I've got some 1 3/4" ****** super comp headers, probe shaft rockers, proform main body for a double pumper and various bits and want to get as close to the high 400's as possible.

Will be going through a brake equipped glide, MSD igition with a 2 step

Oh yeah, it will be in a chopped Morris Minor....

So does the AC heat range start a 1 for cold and go up from there?

 

Ran a similar motor in the mid 70's. On the street it was happy with r45ts. On Saturday nights it was happier with 43s

 

A 42 heat range is cold, a 46 is hot. Almost everything falls in between.
I don't really know where the 441, 443, 436 and 438 fit in.

And I think 61bone meant 43TS, a 43S is a 13/16 plug that uses a crush ring, not tapered.

 

Sounds like you have a mean LT-1 coming to you . 12.5 to 1 , that should put out some hefty HP & Torque . That will be a wicked Morris ! I saw one with a blown 427 rat in it . That's just all motor. Need to send some picture so we can see what you are building .

 

I run R44Ts on a very similar motor with no problems. this would be a good start.

 

Thanks for all the input people, after doing some reading I'm going to go for a NKG race plug, pn R5673-8

Yeah I'm hoping it will be a good motor Retro, my mates had the heads off and it all looks good aparently, painted valley and stuff like that, not a bad buy for $1500, was only missing rockers and carb!

Here's our chop thread for the Morris Retro

http://www.jalopyjournal.com/forum/showthread.php?t=311377&highlight=gotzy&showall=1

 

NGKs are a very good choice. They have never given me any problems and the plugs cover about three heat ranges.