will 1300cc single port heads fit onto 1200cc cylinders

4 posts · joined Jun 2011 · 6 Mar 2012, 11:48 am

#890570

Hi,

I've got a really good 1200cc engine, and I want to improve the breathability of it. I've already sorted out the exhaust with a tuned 4 into one system, and now it's time to look at the intake system. I have an old 1300cc engine that I'm stripping and rebuilding as a 1600, and before I take the heads off the 1200 and replace them with 1300cc heads, I thought I'd ask to see if anyone had done this before, and whether it gave the old 1200 any more power. I know I'll have to cut the 1300 manifold to reduce it's width, but I'm willing to do this if it gives more life to the 1200 (which revs to 6000 rpm ). If anyone has done this, I'd be happy to hear from you. Thanks.😎

whatnow Custom Title Time!

1,000 posts · joined Jan 2003 · 7 Mar 2012, 1:28 pm

#890743

it can be done, see the vintage speed forum at www.thesamba.com as this is covered there in detail.

if your 1200 heads have been modded flow enough to rev to 6000 i doubt that 1300sp heads will flow any better.

coletrickle Wolfsburg Wizard

661 posts · joined Apr 2009 · 7 Mar 2012, 3:09 pm

#890755

I'd be leaving the long motor alone,and looking at a larger manifold t section(1600sptp with modded ends)and a stromberg off a HQ racer 1.1 exhaust rockers ratio intake rockers.and if you could pick up a slip in big bore kit that would be a ripper little engine.I had a 1370?40 horse with illegal vee heads pict 30 scat econno exhaust and it made 48 hp @ wheels.1200s are heap of fun.Keep us posted

chequer57 Seriously Crusin Dubber

125 posts · joined Feb 2006 · 7 Mar 2012, 11:38 pm

#890835

The Vee guys used 113 101 373 or 113 101 371D 1200cc heads.

Other trick other than careful porting is the partial installation of the inlet valve guides.

Formula Vee engines make all their power out of carefully optimising the inlet track and having the in the bottom end balanced.

The Formula Vee rules are so restrictive most decent bolt on bits would make an engine more powerful than leaving it in fvee trim.

Formula Vee, preserving engineering museum pieces in Australia since 1964

countrypiper Learner Dubber

4 posts · joined Jun 2011 · 12 Mar 2012, 5:03 pm

#891538

Thanks for all your advice. I've decided that swept volume is king where power is concerned, and I'm going to convert my 1300 second hand engine into a 1600 and replace the 1200, without mucking around with the heads on the 1200. There seems to be a pretty well priced kit on Classic VW site that should fit my 1300 well enough - or so I've read ( https://www.classicveedub.com.au/cvd_new/part_detail.aspx?parts_id=15189 ). I now need to organise the 1300 case to be bored and the deck height done - then its on with a rebuild (and a few modifications, like an external oil filter!).