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Block huggers vs cast manifolds on P6 lump

Posted: Wed Mar 21, 2012 8:39 pm
by smash
Newbie alert!! Just thought I'd get that out the way so it covers me for making an arse of myself!

I have a 7 style kitcar with P6 Rover 9.25 compression lump - stock apart from offy and edelbrock 500 (not convinced about the Edelbrock and am still wondering about going Holley 390).

Anyway the engine is a tight fit unsurprisingly - it has stock P6 exhaust manifolds at the mo (centre exit straight down). I thought it might be worth putting tubular headers on but as it's tight I'd have to go block huggers.

Is it me or are these bloody hard to find?!! Anyway, I was thinking it wouldbe a power gain but I found some stuff on the net that suggested in a dyno shoot out the stock manifolds may produce better power. I don't really understand how/why

Is it worth me investing in block huggers or are they not worth the money for the marginal gains on a stocker? (they are obviously shiney and look nice which of course is half the battle!!)

Thanks for all /any help! :D

Posted: Thu Mar 22, 2012 8:25 am
by ChrisJC
People only fit block huggers when they absolutely have to, which suggests to me that they are pisspoor!

Tubular headers are noisier than cast headers.

Chris.

Posted: Thu Mar 22, 2012 10:25 am
by kiwicar
Hi
There will be nothing to choose between block huggers and the cast manifolds you have power wise, they are both pretty poor. If you can fit the range rover type cast manifolds with the 4:2:1 configuration both sides they are a big improvment over the ones you have and they will often fit where full tubular manifolds won't. Surely it's a 7. . . can't you just cut holes in the side panels and come straight out the side of the engine bay? that way you end up with a near ideal header set up, straight out the port for about 8" nice wide bend down at the side panel and into a collector and side pipe :?
Best regards
Mike

Posted: Fri Mar 23, 2012 6:47 pm
by smash
Thanks for replies - yeah you're right - I could cut a hole but unfortunately there are already holes cut below centre manifold where a single pipe comes out either side. I'd have to cut extra separate holes for 4-2-1 and it's only been painted last year! I'd have to change it's name from flying frog to cheese grater, lol :lol: