Hello to everyone on the 335 forum. I have just joined the Ford Trucks forum, although, I confess, have been lurking for a few days reading all the posts. The amount of information and helpfulness found on this forum is amazing. I could never find this information here in AUS.
I have a question, or several actually. I am currently rebuilding a 400 Ford motor to go into an XD Fairmont-I know this is not a truck-and I hope you will forgive that one failing-and would like some advice on cam choice.
My car weighs about 3400 pounds, has a 3.23:1 rear axle, has Lukey tri-y extractors, dual 2.5" exhaust with Lukey twin turbo mufflers, and runs on straight propane gas. Have a Gas Research carby and vapouriser, flows about 510 cfm. Will use the single plane Weiand X-celerator with spacers.
The 400 motor will be bored .030 oversize, will use 2V Cleveland open chamber heads, roller rockers, stainless steel valves, 10-10.5:1 Badger Flat top 400 pistons kindly provided by Tim Meyer. The block will be trued, so just enough milled to achieve this aim.
With propane gas I have been told I can run up to 11.0:1 compression (Octane 100-104 for propane). I have opted for 10.5:1 compression. They seem to be mixing more Butane with lpg all the time. This may lower the Octane rating?
I would like the XD to be a daily driver, but also have some mild street performance, up to 5500 rpm at the most. Most of my driving will be done 1500-4500 at most and is mainly stop-start in traffic, although some freeway driving will be involved.
I would appreciate any suggestions on the choice of cam for my situation. I quite like the Comp Cams Dual Energy range. I am told that Propane likes an extended duration on the exhaust side. Has someone a suggestion such a cam?
All suggestions greatly appreciated in advance.
Cheers
Craig

 

First of all Welcome to FTE and the 335 series engine forum!

I think you'll find that most Ford engines prefer extended duraton & lift on the exhust side simply because Ford exhaust ports have notoriously poor flow characteristics. There's been dozens if not hundreds of threads here on cam comparisons so you may find it helpful to use the search feature to help sort out some of the choices.

Recently there was a thread started by Tim Meyer (TMI) where he listed out a whole bunch of cams on his website. You could download it and paste it into an excel spreadsheet to sort by duration, lift, etc.

Overall I think you'll want something in the neighborhood of .510" - .530" of lift and 220 - 230 duration. Some will say that's too radical for the street but on a vehicle as light as yours I don't think your low end performance will suffer. The longer duration will also help lower your dynamic compression ratio because even with the higher octane rating of propane open chamber heads are prone to detonation.

 

Thanks for your prompt reply Bill.
I came across the threads by Tim Meyer yesterday. Wonderful person is Tim. Sent me out the 10-10.5:1 Badger pistons and it took less than 5 days to arrive. Great knowledge base too.
I was wondering about detonation and how far I could go with CR. Your advice Bill has helped a lot. Initially I was going to use closed chamber 302 heads and stock pistons but my engine rebuilder thought I could go higher with the CR.
I will take your advice Bill and compile some more stats on the various cams recommended. Will get back to everyone soon.
Cheers
Craig