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Dart SHP heads

37K views 32 replies 11 participants last post by  vinniekq2 
#1 ·
Hey Guys. The original plan was to get a set of AFR 180's and run a flat tappet cam. After some good info from you guys I changed the plan to going with a Patriot freedom series 185, port and polish and put a hydraulic roller. I went to buy the Patriot heads yesterday from one of ther distributors. They spoke to patriot and patriot said they dont have the cores to make the heads and wont probably wont THIS YEAR!! as they are having finacial issues.

My question is what do you guys think about keeping the same plan but subing the Patriots for the Dart SHP180's?? THe out of the box flow doesnt look great but I know flow doesnt tell the whole storey.

355 SBC 10.3:1 Stock internals
RPM Air gap
Comp XER294
crower rolller rockers 1.6 int - 1.5 exh. (got a deal on them)
Holley 670 street avenger
 
#2 ·
They're iron heads, and heavy castings but nothing great without a lot of porting.

I really don't see any appeal for them unless you're required to use them by racing rules.

Since you were looking at patriot I assume you want aluminum offshore heads- there are plenty of options available for that. Also with that cam id get a 195-210cc port not a tiny 180cc port.
 
#12 ·
If you have heads that flow 250 plus cfm on the intake side with a 75-80% exhaust flow,for normally aspirated engines,,,,I would go with the smallest cc intake runner that gives the flow numbers I want.This keeps the intake velocity higher on a smaller engine.
on a mild 350 I would consider modified vortecs first.any aluminum head that offers CnC machined,flow tested aluminums next,for a race car,go with specialty heads and custom porting.
 
#13 ·
Flow numbers aren't everything. Using the smallest port will result in severe choking at high rpm. There are ways to corectly size the port and the valve for your intended usage, always using the smallest is not one of them. You can get 250cfm out of ported stock castings, that doesn't mean they're good for performance.

Btw excessive velocity is just as bad as inadequate velocity if not worse.
 
#14 ·
I wont be turning the motor past 6500 Tops!!. Probably put a 6000 pill in my msd just to be safe. This will aslo be a street car. Ive read you really dont want to use anything above a 195cc intake runner on the street. Also seen many people say 180 runner is perfect for 350 street motor. I talked to 2 people at AFR one said use the 180's for sure. The other said Because of the weight of my car (2500#'s) he go 195's. Being that im a cheap a** I considered getting a cheaper set of heads(still want decend quality) and port and polish them.
I would like to make 450hp but still have a reasonable amount of tourqe.

Any head suggestions would be appreciated. I can get a set of AFR streets to my door for 1715.00 USD. If I could get a set to my door for $1200 and port and polish and achieve that 450hp goal I think thats the way I would go. Im in Canada btw
 
#16 ·
If your redline is 6000 rpm then you have the wrong cam. For that rpm on a 350 a 180cc runner is about perfect. A cam with about 225 intake duration (.050" hyd) will be about right.

You need to pick a concrete target and have all your parts work towards that goal, not just slapping parts together.

BTW taking about 10cc's out of junk yard vortec heads along with a good valve job and stock valve would actually be about perfect for your goals, and can be done for less that $500. Much less if you're resourceful.

You're making reaching your goal much more complicated than it needs to be.
 
#15 ·
stock 292 angle plug heads can make 450 HP with a decent camshaft.My 67 Camaro used GM cast iron heads,solid cam,850 holley,ran high 11s @ 114,car weighed 3600 ish with me in it.

The afr heads can make more power with less cam,you do the math on cost and drive ability.
 
#21 ·
Heyyou car CNC. I wish I could get AFR's for 1020 (so does everybody I would thnk :) ) AFR's will cost me 1720 usd by the time I have them in my hand. Do you think the dart 200cc head would be to big for 355 street car?? Also that link you posted look like it was for a 383. What do you think those numbers would be like on my setup if I did some clean up on the heads??

Thanks again for the great info
 
#24 ·
most street driven cars dont even need the flow of a 180 cc intake runner AFR head.I use dart 227 heads on my car,its not that Im scared or unaware of what those heads can produce.Just look around at the general posts,hydraulic cams,small to medium carbs,most carbs are vacuum secondaries,lots of dual plane intakes,small tube headers,2 1/2 inch exhaust or smaller,,,,why would any of these applications need 200 plus CC heads?
 
#25 ·
I have used Darts for years and refuse to buy any other name brand to race with for two reasons reason #1 out of the box they out flow all other competition and #2 they are truely a track proven performance head I have a set of the 230 pro1's on a 410 small block as we speak the shp series are nice for any app and I believe the dude that replied about the cast iron heads was probably thinking of the sportsmans which are still excellent heads but you won't be disappointed with any Dart head you pick!
 
#29 ·
I have been on Comp Cams CamQuest. I went thru every HYD. roller cam they have recommended and according to the dyno results on their cams you wouldn't come close to 450 Hp with your parts. Now if you use the Dart SHP heads with a Comp solid roller XR280R, 2500-6500 rpm range, single plane intake with a 750 cfm carburetor,3.73-3.90 gears and a 3000 stall it will put out 424.1 hp@ 5500 and 436.7 lbs of torque @ 4500 rpms. With the largest Hyd roller hp was like 387 hp @ 5500 with your intake and carb. If you wanted 450 hp should have done some research and built a 383.
 
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