Ford Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1 (Edited)
Hi. Forgive me if this is the incorrect place to post the following. I'm new on this forum and well, any forum really. I have some (but limited) technical understanding of engine combo's, so hoping for some guidance on cam selection for a 393 cleveland stroker which currently has Aussie 302 2V close chamber iron heads. My setup currently runs sniper TB efi which I love and want to keep (good for approx 600 HP). It has a comps cam xe 274h hydraulic FT cam.

I'm using an AFD highrise 2V intake and 1 3/4 tri ys extractors. From memory (the motor was built 5 yrs ago now) it was running 10:1 compression with the stock 2V heads. I'm running a 3500 coan stally and I have 3:27 rear gears. C4 race build trans all in an XW sedan around the 1400kg mark. This is a street only vehicle at present and will more then likely stay that way. I realise the 2v iron heads are a big limitation overall for the 393 stroke, but it seems to be a great combo on the street. Can light up the rubber any time I feel like spending money on new tyres. I have found someone selling a set of complete AFD 4V's with 57cc chambers and 225cc port volume for a very good price with low Km's, which is why I'm contemplating 4V's over the 2V AFD's.

Can I still have a great traffic light to traffic light combo if I add the AFD 4V's with the right cam choice? The intake that comes with the 4V's is a TFC highrise matched with the 4v AFD's. I realise they are a head designed for racing apps, but with a change of cam, and extractors, can I improve my off the line performance with the big ports? I'm not planning on big RPM's for the strip. Maybe I don't even need to change the cam? I dunno? Or should I stay put on the 2v irons? The cam will need to work with efi if changed for the 4V's. If this is a good idea for an upgrade, apart from possible cam and extractor changes, is it just bolt on? Will I need to change push rod lengths, rocker (crane gold series roller rockers) geometry or the like. I'm not sure if the aluminium heads are taller then factory 2V iron heads etc. Also the comp will change with 57cc chambers in the AFD's. From memory, the factory aussie 302 chambers are in the 64 -69cc range? Will the smaller AFD chambers cause detonation? I run 98 octane (australian fuel which is pretty good) and never have issues with detonation with my current heads/combo. Thanks in advance for your help.
 

·
Super Moderator
Joined
·
8,280 Posts
Unless I missed something, I don't believe you ever mentioned any specs on the cam. I'm a Yank, not as familiar with the Australian products, but we all run under the same laws of physics. There's a lot of products out there these days, to give you a definitive answer would require a bit more on your part. For instance, if your present cam is near stock and you're wanting to go just a little more aggressive, the rest of the valve train will probably do all right. Since you are going 4V, it is an opportunity to change the valve train around. You're less likely to detonate with aluminum heads as they dissipate the heat better than iron heads. State side, I've seen people run near 11 to 1 on 93, I'd imagine you an get close to 12 or better with 98. Once again, there are variables here not disclosed. Sorry for such a vague answer, but as I said, there's so many selections these days. You're better off picking a few key ingredients that fit in your car and budget, then work outwards with what's compatible.

I included a link to make calculating your final compression ratio:
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
Thanks Catskinner. Yeah, a bit lazy on my part regarding the cam specs. I posted the cam, but didn't post the specs. It's a comps cam extreme energy 274H haydraulic FT.
Duration @ 0.006":
274° / 286°
Duration @ 0.050":
230° / 236°
Max Lift w/ 1.5RR:
.487" / .490"
Lobe Separation:
110°
Lobe ID#'s:
5445 / 5208
Intake Centerline:
106°

Selected originally when the engine was built for the 2V iron heads, 2600 stall, 2:92 rear gears, a standard Edelbrock 2V performer intake and 750 Holley Carb. Now running holley sniper efi, 3500 stall, AFD 2V highrise intake and 3:27 rear gears. I like doing a bit of highway driving and as it is, I'm sitting on 3100 rpm at 62 m/phr. So wanting to avoid going any lower in the rear gear if possible. Thanks for posting the engine comp calc. I'll have a look at that. Maybe if I want a bit more, with the other changes that Iv'e made, maybe a simple step up in cam (not too much) would still be ok with the 2V's?



 

·
Super Moderator
Joined
·
8,280 Posts
As always, it'd be more effective with aluminum 4V, but coin does come into play. I'd say you should be fine.
 
1 - 4 of 4 Posts
Top