Horse Power Guestimates...

MustangGlx

New Member
Apr 2, 2003
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Connecticut
Alright, im at school, Going to wyotech and i will soon be getting a student loan to build a stroker motor, i have a partlist thrown together here, what kind of power do you think i could make, or are there any parts here that you think i should use something else for?

351w block
scat forged 408 stroker rotating assembly with H beam rods and forged JE pistons
AFR 185cc aluminum heads
Compression ratio would be somewhere in the 11.5:1 area
mildon deep sump oil pan
a high volume oil pump, not sure what though
comp cams hydrolic roller cam
cam specs: 513 lift 282 durration intake, and 529 lift 289 durration exhaust
110 degree lobe seperation
crane cam engergizer full roller rockers
Mass-Flo EFI mass air flow fuel injection set up with 36# injectors
holley electric fuel pump and regulator
and im thinking hedman torq-step hedders

i think thats all the info you should need to make a guess if i forgot something let me know, i know you wont be able to get an exact based on a guess, im just looking for a ballpark figure, thanks
 
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Well, I'm not sure on HP yet, but I can tell you a few things to do to optimize the setup....

First get a decent port job on teh 185's. You won't need something as big as the 205's, but a good mild port work can go a long way.

Be careful with the compression as high as 11.5:1. It wouldn't be a bad idea to go a little lower (11-11.3) just to stay on the safe side.

You're telling us the camshaft advertised duration specs. They don't mean squat. Tell us the duration @ 0.050. You could also benefit from a solid roller over that hydraulic roller. Solid roller camshafts would help the rev and would ultimately make more power.

If you want EFI, go for it, but I can't comment on the setup you've chosen. Personally a trusty 850 4150 HP Holley would be my suggestion, 750 if the cam is smaller.

For headers your'e going to want something that is a 1 7/8 diameter primaries due to the large CID of that motor.


That's all I've got for now. I'll come back later.
 
alright, sorry those cam specs were advertised, at .050 the specs are
230 duration intake 236 durration exhaust, the lift numbers were vlave lift with factory rockers, but im not sure what the ratio was on the factory rockers, its a later 351, with a 9.5 deck hight, the rockers im looking at are available in 1.6 and 1.7 but i dont know which one to get
 
351carlo said:
You're telling us the camshaft advertised duration specs. They don't mean squat. Tell us the duration @ 0.050. You could also benefit from a solid roller over that hydraulic roller. Solid roller camshafts would help the rev and would ultimately make more power.

For close generic gross duration. 282+180= 462/2 = 231 @ .050

Again this would depend on ramp rates etc. . .

I do agree that the cam seems relatively small for a 408. Torque motor, yes however the cam would be done by 5600 RPM. Also the lift isn't even close to maxing out the 185s. I would go with a Victor Jr head or Windsor Sr, something with 200cc of intake runner because if you plan on taking a 408 to 6000+ it will need it. Something in the mid 240 range at .050 sounds decent along with at least .560 lift. With the setup you have suggested and stock AFR 185 heads I would say peak of 510-520 at 5600. Torque would probably be past the 530 range.
 
57fairlane said:
For close generic gross duration. 282+180= 462/2 = 231 @ .050

Again this would depend on ramp rates etc. . .

I do agree that the cam seems relatively small for a 408. Torque motor, yes however the cam would be done by 5600 RPM. Also the lift isn't even close to maxing out the 185s. I would go with a Victor Jr head or Windsor Sr, something with 200cc of intake runner because if you plan on taking a 408 to 6000+ it will need it. Something in the mid 240 range at .050 sounds decent along with at least .560 lift. With the setup you have suggested and stock AFR 185 heads I would say peak of 510-520 at 5600. Torque would probably be past the 530 range.

alright, if i go with a more agressive cam one ment for a higher rpm, for example this cam says its good to 6500 rpm at comp cams site, it has 236 intake 240 exhaust duration and .555 lift intake and .576 exhaust, and the victor jr or windsor sr heads or maybe some AFR 205s or trickflow high ports what would i see for power?
 
MustangGlx said:
alright, if i go with a more agressive cam one ment for a higher rpm, for example this cam says its good to 6500 rpm at comp cams site, it has 236 intake 240 exhaust duration and .555 lift intake and .576 exhaust, and the victor jr or windsor sr heads or maybe some AFR 205s or trickflow high ports what would i see for power?


ok, when looking at a cam, and its rpm range, the manufacturer is assuming that you are going to be building an engine within a few cubic inches of the engine the cam was designed for. a cam that works well in a 289 or 302 inch engine at 6000rpm, would work well in a 351 inch engine at something more like 5000-5500 rpm. the reason is tha larger engines can tolerate larger cams better than smaller engines. in this case you are adding 57 cubic inches, and thus you should go up one cam size to get a similar result rpm wise that you would with the cam you selected for a 351w engine.

right now you have an engine that will be a torque monster up through about 4500rpm, and it will have an hp peak at around 5000rpm. if this is a street engine, that is actually rather perfect, and i agree with the tq and hp numbers that 57fairlane indicated, though i think he might be a bit high.
 
MustangGlx said:
alright, if i go with a more agressive cam one ment for a higher rpm, for example this cam says its good to 6500 rpm at comp cams site, it has 236 intake 240 exhaust duration and .555 lift intake and .576 exhaust, and the victor jr or windsor sr heads or maybe some AFR 205s or trickflow high ports what would i see for power?

rbohm had a good response, all of the RPM suggestions are going to be for a 302 or a 351.

I would say that comp cam you came up with would pull to about 6000. Probably 530 hp. I would figure about 30hp more with 205s or Victor Jrs.
Also what intake are you planning on running? TFS-R? Victor Jr.?

I guess that would also correspond with what RPM you plan on running and what the intended purpose of this motor is . . .
 
Very interesting numbers, Not knowing much about cams I am even more intrigued as I am building similar engine, 351W with the scat 408 stroker kit (using Ross pistons instead, possibly dished, depending on what compression i am looking at 10.1 ish) but I was planning on using the Windsor Sr heads with full port and polishing. Haven't decided on the intake manifold as I want to make sure it fits under the hood (67 shelby style). I was looking for similar hp numbers with the climax at around 5000-6000. would this be possible with the lower compression? I just rather stay with the lower compression for reliability and using pump gas.
 
I think the big question here is what do you want to do with this car?

- If this is an engine that will be seeing a fair bit of street time then I reccomend dropping the compression to at least 11.0 and leaving everything else (including cam) the same.

- If this is mostly a race motor, I'd go with a more agressive cam and leave everything else the same.

With a street tune I could see this engine putting out around 400rwhp. With a race tune...450rwhp.

I just want to remind everyone that stroker engines tend to make their power down low..and tend not to like the higher RPM's. Especially with a large stroke like this one.

My only other note is that this is looking like 1 expensive motor! Plan on spending $6000-$8000 ($2500 just for your EFI system) Do you really want to be spending your student loan money on this? I've never been a fan of spending money that I don't have...especially on toys.
 
I recommend better heads than those. They will not flow near enough for you to really get all the power out of that engine. I am not saying to slap on a freaking 230cc head, but the 185's are much too small. I also recommend a bigger cam. You want it to be torque which it will be, but with a stroker that is never a problem. You can spin it if you want, but I think if you get a cam that will max it out at 6000rpms you will make great hp numbers and also keep a good torque curve which won't peak too high, making for a very fun street engine. Drop your compression you are at sealevel and that will not run on pump gas unless you got a set of webber carbs to go with the aluminum heads, and even that may still ping. Also don't forget to build all the essential components with ARP hardware also.
 
alright sorry i havnt replied sooner, ive been real busy with school, alright i want to do a street/strip car with the motor, a toy for the road and track, but probobly not regularly driven i was going to put it in my 69 mustang but i decided i like that the way it is now, so im thinking about doing a fox or sn95 mustang, the intake is here http://www.massfloefi.com/ they offer the sysem for 3000, and you can get it 1800 if you have the wiring and computer for a factory ford fuel injection set up for pushrod v8 with mass air flow, 89-95 mustangs i think, either way i have the wiring already so the intake and fuel injection set up would be about $2000