Hey guys im finally getting around to starting my motor buildup. What plans i had for the 406 are gone, as my engine builder talked me into a 383. Im ordering my rotating assembly next week (a good scat crank, weisco forged pistons...cant remember the rods and clevite 77 bearings) and im going to have a decision on heads very soon. Ill be using a HSR (he tried talking me into carb) im not sure on the cam yet but it will be a rollor. Do i want to use solid rollor or hyd. rollor? He says that he would use dart 220cc heads on this motor but from what i have been reading their are better heads for around that price range (AFR, Brodix, canfield, trickflow, ect. ) and i thought 220cc runner would be too big on a N/A 383. Im trying to get 500-550 n/a hp w/ 10.5 comp. out of this motor and i dont think that is possible with the out of the box dart heads. The majority of the people here think the AFRs are the best out of the box but what would be next to them? I would prefer something with 195cc-200cc to keep my power lower and a 1205 port size to match the HSR. Ive been leaning towards the Brodix RR200. How do these flow comapred to the dart pro1, dart iron eagle and the trickflow KD 23 heads? I need to figure out what heads before i order my pistons!! Any help would be appreciated!

 

for 500-550 hp on a 383, i'd go solid roller... although a big hydro will do it. something with 240 degrees duration should push 500hp
theres an article on here with a test with hsr and minram that made about 500hp on a 383 with ported trickflows.. cam was a 236/242 grind i believe... comp cams xe286 or something like that

heads.. competition ported AFR 195's should work.. but it wouldnt hurt to go just abit bigger to the 210's although i think the intake gasket on those is a 1206 and hsr is a 1205 and your gonna have to match them


look into the new Patriot performance heads.. the flow numbers are advertised to match AFR if not exceed them, and are priced for 1300-1400 a pair complete

 

Those patriot heads look very impressive!! How long have they been out and why is nobody using them? They seem to flow better than the TF, brodix and darts. The springs will take a high lift cam too. I didnt see what the port gaskets were, if they are 1205 i would probably buy a set! Anybody know anything about these heads?

 

the patriot heads are just starting to get big. They've been building heads for a while, but not really pushing through any of the larger retailers. - I haven't had any personal experience w/ them yet, so I'm not gonna say good or bad about them.
- I do agree on the larger cam to make the power you want, but the larger cam changes drivability of the car. Not that it won't be drivable, but it'll drive very different. My cam is pretty big, especially for a 355. I run in the 11's and it was/has been a daily driver(down now for a lot of work). At my land barge status of 4161lbs, that's good HP.
- As long as you don't mind the tuning, don't give up your efi. I'm going back to it, with the megasquirt ecu.
- Why'd you give up on the 406? Larger bore takes more advantage of better heads. Why do you think pro stock runs such a large bore and short stroke?(cubic inch limit requires less stroke to accomodate larger bore)

 

another thing, on a street car, don't get too carried away w/ static compression. Look at your dynamic compression(calculated with cam specs). - I'm running 10.989 static on pump gas, no issues. - something like 9.8 dynamic....

 

I was talked out of the 406 by my engine builder because of the thin cylinder walls and the cooling issues. He said a more reliable engine would be a 355 or 383 and i could get as much hp out of a 383 that i wanted. He said he builds 700hp NA 355 often but i think he was referring to circle track motors.
Shagwell could you please explain on static and dynamic comp. a little? How do you come up with static compression out of your dynamic comp.? BTW the cam i was thinking about using is this here Would this be sufficient with my setup?

 

I just talked to patriot performance and they said these heads take a 1206 gasket. How much port matching would be required to the HSR which requires the 1205? The good thing about these heads compared to AFR is you dont have to wait 8-10 weeks to get them, the springs take up to a .650 hyd. roller cam, cost a bit less and flow about the same. Anybody wanna buy a set and try them out for me?

 

thats a bit of a circle jerk(circle track) cam. install at 106 centerline, 110 seperation? sounds more like explosive power through a tight rpm range(out of corner hard, pull down the straight, back down into a corner) - you gonna run an auto or manual trans?
- anyhow, to figure dynamic compression, take you static compression and you cam spec, go on the Keith Black website and use their compression calculators. dynamic compression is running compression. Larger cams bleed off more compression, therefore lowering the actual compression ratio, which is why you run higher static compression with bigger cams. - remember, your to be accurate on your stativc compression. you'll need the actual deck hieght of your motor(GM blocks vary), piston height at TDC, head chamber cc, and head gaset cc. - All of this can be done before getting the pistons, which allows you to figure out which pistons would be best. You can get the specs on the pistons from either the manufactures' catalog, or from their website. Take that info to KB's website and play w/ different pistons & head gaskets to get the numbers you want.
- yes, GM 400 blocks are notorious for cooling issues. The siamese cylinder walls complicate things, but with the proper cooling system they'll be just fine. - I do agree a 355/383 are great motors though(my current is a 355, new is 400 block de-stroked to 380ci)
- as for the port work on the intake, simple. Aluminim grinds easy. For what you're looking for in power, port to the 1206 and have fun.
- sorry this is kinda long