The V8 Owners Forum -

There are a few GMC/Detroit 6-71 and 4-71 blowers on ebay in the States and some say- needs to be converted for gas- so you can use it on a typical suck through setup, I thought these were made to run wet?
Anyone?

I would go for something like a Mcloud or AP Racing clutch, plus a nice lightweight flywheel. I picked a super lightweight aluminium flywheel and twin plate AP racing clutch for £400 off ebay. Yes it was an expensive outlay, but I know it'll handle a lot of power, and since its in an MGB I'm in a s...

Cool thanks for that- nothing like a challenge!!! I'm also trying to finish a Jag V12 bike

I dont really know what sort of torque my engine will be knocking out- 3.9 Supercharged with edelbrock 500cfm carb and hopefully a 100 shot of nos, around 400 ft lbs?!
Any guesses so I know what clutch to get?!

Thanks, still got my eyes out for a 4-71 GMC blower though but typically the wrong one is far more common- the 6-71. If one of these was underdriven it would do the same job but surely if running a lot slower it would be doing less work for the same outcome and the charge temperature would be a lot ...

Why do decent clutches seem so expensive though?!!! I dont want to spend £300/400 on a clutch either!!!!!

Not a bad idea but I dont think the air rushing over the surface would cool much atall- it would need fins or some kind of heatsink inside for the air to get into more contact with the nice cold ally I think! Also there may be trouble when the block warms up to 80 odd degrees and expands and the inl...

Hi, have you got any pics or really useful hints as I am just starting an MX5 V8 conversion!!!

Thanks Tom.

Ah this helps, though you may have all known it already..!!! "The GMC types are rated according to how many two stroke cylinders, and the size of those cylinders, it is designed to scavenge. GMC has made 2-71, 3-71, 4-71, and the famed 6-71 blowers. For example a 6-71 blower is designed to scavenge ...

Anyone think the larger of these two would be any good?
http://cgi.ebay.com/ebaymotors/3-71-3-5 ... dZViewItem

I was thinking a similar thing but then have thought- the air coming from the blower is going to be over 100' and the water in the manifold will be about 75/80! So..... it may actually do more good than harm leaving it! Also I dont see what the outlet on the back of the EP is for as like you say the...

lol the corrosion is the disgusting greasy oil and crud that is smothering the whole engine as I think it has had a pretty un-loved life... you should have seen the amount that was covering up the end head bolts- I was picking it out like golf balls of muck!!!

I've always found this: http://www.mototuneusa.com/break_in_secrets.htm Very intriguing......And a few people who I've know to follow it have had very good success with the engines feeling much more flexible than similar 'normally' bedded in ones :) Have heard that before- is quite tempting to give...

Well after some fidling around this evening I sorted it- I drilled out a bit with an 8mm drill then very slowly and carefully burned away at the broken extractor with a plasma cutter, drilled out and still would not come out so I just re tapped the hole and blew the swarf out! Good ol plasma cutters...

Most of the benefit is from smoothing out the sharp corner which the mixture has to flow around before it enters the cylinder then ya? And the little bit around the valve helps the combustion...