Received Two Different Answers From Manufactures on 393 Stroker


New Member
Apr 8, 2003
Austin, TX
I contacted the AFR and SCAT technical service guys and asked which combo to use for my 393 stroker. The options were AFR 205's and Vic Jr. intake or AFR 185's and RPM intake. I explained that the car was a 70 Mach and it would be used mainly for the streetand a weekend cruiser. The AFR guy said go with the 205's and Vic Jr. The SCAT guy said the 205's and Vic Jr. are a waste for my HP goals which are around 500 at the flywheel. The SCAT guy recommended 185's with a RPM intake and insisted that is all I would need for a street car asking for 500 HP goals. Here again I am uncertain even after askings the pro's. I told them that the car would be for the street and would not see high revs. The AFR guy said the 205's will make more power from 3000 RPM and up and that the 185's would quit making HP at around 6500 RPM. The 205's would also show a little loss down low and the 185's would be more responsive down low. What to do?????
  • Sponsors (?)

Full disclosure: I am not an expert. And just cuz a guy answers the phone at a company doesnt make him one :)

If you want 500 HP at the flywheel, you are looking at a really street-unfriendly motor. Maybe you can do it and tolerate it on the street (automatic trans - nuh uh), but it will take Smokey Yunick levels of tinkering to smooth it out (assuming a NA motor). Is this a magic number for you?

Second, I would get the 205s. A 393 and that HP goal will want the 205s. JMO.
I disagree!! 500Hp at the flywheel these days is VERY attainable and very streetable. My 331 makes 415hp @5400 rpm and 445ft lbs of torque @3800 rpm. I can idle in traffic all day and cruise around with no ill effects and I get better than 20mpg on the highway, my mom could drive my car. No secrets combos either, JE 10:1 pistons, Edelbrock performer RPM heads, RPM intake and a comp cams NX264HR cam with mac longtubes and 2.5" full exhaust. A 393 has a whole lot more potential than a 331.
Why don't you run both profiles on desktop dyno and see if the numbers you get are satisfactory and where the power band kicks in. Then go from there. Email me all the stats, I would even run them 4 u.
Id go with what AFR says. Scat doesnt do heads do they, I would think a manufacturer that does heads would know what best to recommend to ya. I'm very pleased on how our 408 performs with the 205s and vic jr intake. Has very good low end TQ and pulls hard up top. Cant compare to the smaller heads though.

Did you give the AFR guy a cam spec? That will also help decide which heads.
I'd start out with the AFR 205s over the 185s.
You're going to have mind blowing torque with either head, I mean we're talking near big block cubes here.

The 205s will allow further HP potential in the future.
I could see using the RPM intake for a while, especially to keep the motor a tad more mellow. The Vic Jr. intake could always be swapped in at a latter date if/when the need for more HP grows. The way I see it, its a lot easier/cheaper to swap intakes than it is to swap heads.

Another alternative to the AFR 205s would be with Edelbrock Vic Jr heads.
A little cheaper and has plenty of HP potential.
I would definitly say the 205s would produce tons of torque with a stroker and RPM intake. I tried real quick with Engine Analyzer to run this combo. Whatever i do it only gives a few HP credit to a stroker, anyone know what im doing wrong? That is the motor Im gonna build so im real interested. Has anyone seen anyedelbrock dyno tests with a stroker?
I am saying I don't need to build a high revving engine because I am building the engine to run on the street. If the 393 needs the 205's and Victor Jr. to run at it's full potential, then that is what I will do. I just don't want you guys to think I want to build a oval track high revving engine that will be mostly for the street. Again, I am building the 393 for torque and not having to rev up to 6000 RPM to make HP like you would need to do on a stock 351w.
I see. The 205s and the Victor are less revvy on a 393 than a 302, that's for sure. Using the dyno chart on the Edelbrock website, a 393 with the rpm package would be just shy of 450hp at the flywheel. With the 205s and Victor, you may get to your holy grail of 500hp, but it will likely be at 6500 rpm.

If I may ask, why 500hp? A torquey 450hp motor will provide tire shredding power on the street. I think you would actually be happy with both motors that you are suggesting.
Your right, 450 HP will be more than enough. I just put out a number. If I can make a solid street 450 HP street engine with the 185's and RPM, I will be happy. I have just heard so much about the 393 needing the extra air due to the extra cubes. I don't want to starve the engine.
I feel as though i can add some valuable experience here. I have a 393 stroker with AFR 205cc heads and a victor jr intake in my 66. I'm currently running a mild solid roller in it. The motor naturally aspirated made over 450rwhp which is approx 535-550 hp at the flywheel. Dont worry about torque. You will have MORE THAN enough. Even with the solid roller the 205's are really not enough head for a 393. My car make peak HP at 5700 rpms. Hardly a high rpm beast. She made well over 500 lb of torque at very reasonable rpm levels.

If i had to do it over I would go with the 225 AFRs as i wanted a hp peak at 6500 rpms. Remember this is BIG_BLOCK size motor with small block heads. Run as big as you can.

Ohhhh and my car is perfectly streetable. Pulls cleanly at all rpms and idles at 850 rpms with a nice lope.

GO FOR IT!! You wont regret it.
wickedmach1 said:

What are the specs on your cam? Are you using 1.6 rocker arms? What size carb are you using? Thanks for the help.

I have a comp cams street roller in it. Off my memory it is 248/254 duration at .050 and .612/.621 lift with 1.6 rockers. I am using a 750hp holley. The car is VERY streetable and a torque monster with this combo. She will shread the tires at any rpm in the first 3 gears!!

Have fun!1