View original topic: Tech guidance - 1300 heads and Weber 34 ICTs on a 40hp
k9hdlr Tue Apr 04, 2017 6:21 pm

Quick question for you experts out there. I am new to the air cooled scene but will be upgrading my stock 40hp with a set of NOS 1300 heads and a pair of Weber 34 ICT's. Can anyone tell me what rockers will fit the 1300 head....are 1300-1600 all interchangable, or must I select a set that specifically state 1300?

I want to go with the ratio rockers at 1.4 Suggestions on brand and material?

What length push rods will I need to go with? Should I go with aluminum or chromoly push rods?

Will I need new push rod tubes for the change in length? If so, what options should I consider?

Any special considerations I'm missing?

Thanks in advance for the info! Love the forum and the prospect of waking up my little 40hp

txoval Tue Apr 04, 2017 7:32 pm


k9hdlr wrote: Mr. Motorhead wrote: earthquake wrote: I think you can do it, if it was me I would try to find a set of DP 1300 heads, they were used on European motors.

Just in case anyone is interested, I have a pair of freshly built 1300 DP heads that don't have a home. PM me for a price if you want them.

Do you still have the DP1300 heads?

gregson1 Fri Apr 07, 2017 5:55 pm

I bought these heads from Matt and they are now installed on a long block. I will tell you what I've done, so far, but I can't tell you how it's going to run because I'm still trying to fit the sheet metal and a Vintage Speed muffler because the engine width is odd.

The case is the original engine for my wife's Karmann Ghia, built in March of '65.

-DPR 69mm Counterweighted crank
-VW 40HP rods, big end narrowed
-VW flywheel, 200mm, O-ring, 6V ring gear, 8 doweled, lightened to 15lbs
-Cofap old style 40HP P & C 83mm Big Bore kit
-VW 1300 DP heads
-W100 Engle Cam
-Bugpack lightened lifters
-Gene Berg O-ring 26mm oil pump, 8 mm studs

The pistons required no clearancing for either the crank, case or rods. The case did need just a little clearancing for the rods. I also had machine work done for cam bearings.

The case had 10mm head studs, with case savers, already. I found 4 10mm short top head studs, and just used the stock nuts and washers. I had Rimco make me some custom cylinder shims to get an 8 to 1 compression.

I used 40HP push rod tubes and stretched them just a bit. I decided to use aluminum cut to fit push rods and they were cut to a custom length after I set up the rockers. Each side had a slightly different length to help maintain the rocker geometry.

The rockers themselves are stock 1.1 VW, but the side of the rocker that faces the valve was machined back just a bit to give the Porsche elephant feet enough room for adjustment and to set the perfect geometry when contacting and pushing the valve. I used a set of CB solid rocker shafts/shims, and ended up needed no rocker stand shims.

It's no RPM engine, but should produce some nice power. I set it up for a dog house cooler and will use a thermostat, so I'm hoping for some decent cooling. I have both 019 and 010 distributors, and will probably use Kadrons, at least to start with, and then go from there.

I hope it works out and should know over the next month.

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