Ironing out some crinkles

[AP1995V6]

A few questions regarding an engine I'm building. I'm just gathering parts for it right now, and I want to get some input as to what will work and as to what won't work. I'm getting information for several sources so I figured I would come here to put another source on the notch. Can't have enough info, right?

I'm building a 393, and keeping N/A for now since I don't have the means to purchase a blower right now. I want it to have around 9.5 c/r, but I can't really pick out the pistons yet since I need to have a combustion chamber size first. I want the blower to push out around 9psi tops. I really haven't look at it in terms of "I want this much power so what build do I need," but rather in terms of "I want this build so how much power will I get."

It's coming time to decide which heads and cam to get. I want to buy one set of heads and be done with it. I intend for this engine to be a 393 with a blower so I was looking into AFR 225s. Will this be too much of a head for a N/A 393? Would something smaller like a 205 be more ideal? I really don't plan for the engine to exceed 6500 rpms since it's a street car. If all else fails, I have the stock heads that may or may not be cleaned up. Their condition is quite questionable.

As far as the cam goes, I don't want anything more than a .600 lift. I want a cam for the N/A 393 since it won't cost an arm and a leg to replace like the heads would be. I want the curve to remain very similar to the stock curve but allow more breathing, of course. I haven't done much research on cams yet so I'm clueless as to what would be available as good options.

Perhaps this is a half-baked plan for an engine build, but I came here looking for guidance and answers.

Also, I saw someone on here with a sheet-metal box intake on their 351, and they said it easily cleared an R hood. I would like to get some more info on that because I really don't want to get another hood to clear the giant intakes.

 

[Davin]

To respond to your question - The AFR website notes indicate that the valves on the 205 and 225 are the same size. The main difference seems to be that the 225 exhaust port is raised higher and is 10cc's bigger. The notes suggest the the idea RPM range for the 205 is 3500-8000 and 225 is 4500-8500 so I'd suggest the 205. I would actually recommend the 185's for the street though because they are build more 1500-6500 range.

As far as your plan goes though, it doesn't seem you have one. In the nicest way possible, I want to say that its unclear from your post why you even want to do this (whatever this is). You said you wanted a SC 393 with a NA cam and that you don't have any horsepower goals and you sound concerned about spending. I'm just wondering what your real goals and limitations are here. Also, what kind of drivetrain, chasis, suspension, and braking mods have you invested in? A well turned 393, especially SC would tear up a stock drivetrain and would be unsave with stock brakes and chasis..so let me recommend that you establish some kind of clear goals to plan around and go from there...(hope this doesn't come over as harsh, I'm trying to help)

 

[AP1995V6]

It's a long term goal. I'm probably going to get a viper spec T-56 this summer.

I've talked to D.T.S. about a custom 8.8" rear-end so that is in the works.

And I have 13" brembo 4 piston calipers on order.

If read into chassis stiffening parts and stuff that I'm going to be getting those relatively soon once I come to a decision on what I want.

This is definitely not going to be done by this summer nor do I intend on driving it any time soon. It's a long term project.

If you read the message, I want a NA cam because I'm going to use the car before I get the SC. I don't want to drive around in a car with a blower cam without a blower. See where I'm going with that?

I wasn't really sure bout the head choice since a 393 is going to need alot of room to breathe and I thought the 185s might end up choking the engine.

And yes, I don't have HP goals. I want whatever I get from a 393 and SC (when I get it) on pump gas. Making power isn't really issue. Building something that isn't going to suck is the issue. I'm going to use a 393. The question is which parts should I use on it to make it breathe really well.

The current goal right now is building a NA 393 that will accept a SC without having to upgrade everything (heads, intake, bottom end, etc).

Well, I suppose there is one restriction. I want this to remain under 600rwhp. I don't want an insanely powered car. Something to drop jaws at shows and have fun at the track with.

 

[94Blue302GT]

First of all, do you have a good block you're starting with? a 393 with a blower is gonna make mad power that will split a stock block, even a 351 most likely.
I"d go with the AFR 225's, and either a real high flowing intake, or even that homemade intake. I'd suggest going with a single turbo kit, really just about the same amount in cost as a blower with full exhaust and the supporting mods, and you can have the adjustability of the turbo, and more efficient power.

If you want under 600 horse...
your 393, afr 225's, a custom grind cam, trick flow intake, long tube headers and full exhaust, 36 lb injectors, maf, etc. and a GOOD tune, and you'll prolly have 400-450. More than enough to turn heads, and with some tweeking/etc. you could prolly push 500. The rest put into the suspension and rock that car down the track.

 

[AP1995V6]

I have a Dart Iron Eagle Block.

How far will the 225s shift the rpm range for a 393? I've read the stuff on AFR's site, but I want some info from someone that has experience with that.

I want to keeping the operating range under 6,500 since I have no intentions of making this a high rpm car, but I also need something that isn't going to make the engine air deprived.

Head choice has been a real problem for awhile now. I really don't know what to go with.

 

[Davin]

Cool. okay, sorry about the confusion but that makes a lot more sense. The way I read it, AFR seems to think that the 205 is a better head for lower RPM power than the 225. I'm guessing that this is because the smaller intake/exhaust ports (ports, not valves) on the 205s will keep the exhaust velocity up. I think that before you add the SC, this will keep your power band lower which is nicer on the street. When its time to add the blower (assuming this is long term), you could always have the intake and exhaust ports worked by a machine shop. You wouldn't need the valves worked so it shouldn't cost that much.

BTW, I run a "blower" cam on my 347 NA and it runs great. Rick at AFM recommended it to me. I say blower cam b/c the exhaust duration is a little longer than intake. I didn't go huge on exhaust (header runners), so the velocity stays up. I think it would be a mild compromise for not having to replace the cam when you add the blower.

 

[AP1995V6]

Cool. I'll check out more into the 205s then. I've read around here that some people's cars ran like crap with a "blower" cam and not actually having a blower, but if I can get the car to run good with that kind of cam, even better. Yeah, it would definitely be really convenient to not have to do a cam swap when I add the blower.

Thanks!