Putting my heads on soon and I wanted to know if you guys think the 200CC heads are to big for my combo? What i have is a 355 with 9.5 comp.MAF, and a HSR with 24lbs injectors, COMP cam 08 502 8 218 int./224 exh 0.495 int./0.503 exh. with the summit racing 64cc Chamber, 200cc Intake Runner heads,
and 2800 stall with 373s.I dont want a bigger cam because it is for the most part it's a street car .Im hoping these heads don't kill my low end. THANKS.

 

They will work but cam is abit small to take advantage of it. What heads are they? Abit more compression would help esp if aluminum head

Keep in mind alot of 200 cc heads are 1206 gasket port size and hsr is 1205. Depending on hsr year base you have, it may or may not have material to port to match

 

They are Summit brand. http://www.summitracing.com/parts/SUM-162111/

 

Good heads just should try to get abit more compression and id run the 503 cam to really have a good running combo but what you have will work. Mill heads down .020-.030 to get abit more compression would really be nice tho.

Unless you want it to run on 87 oct or something then leave as is but leaving abit of hp on table. Just my two cents.

Another thought is the xfi 268 cam and beehive spring kit or other stiffer dual spring kit. Extra lift would help that car make more overall power and low end as well as extend rpm range. That cam on a 110 lsa would be real fun

 

OK thanks. looks like im going to order a new cam. The 503 is not too much bigger and I would always kick myself if i did not do it now. THANKS

 

If you already have the cam then use it. Just do 1.6 rockers. If not you can go bigger on cam and it be nice to also shave heads for tad bit more compression. You have 3.73 gears which will favor the bigger cam and make up for any lack of low end.

 

Two comments really here.How much lift will the heads handle before they have to be machined??. I'm thinking you do need more compression,but rather to cut the heads, maybe to deck the block might be a better way to get there. 200cc's I don't think your going to see them come into play until 3000 to 3500 grand.

 

I believe the summit brand heads are brodix castings. They should be good to well over .600-.650.
With hsr the torque peaks with either cam will be in the mid upper 3000 range but be fairly flat across the range. 2800 stall isnt to bad for the combo bein a street car esp with 3.73 gears. Track id run 3600 with 503 cam.

I tuned a low comp 190 cc headed hsr 360" sbc with much bigger cam 230/236 .570" and it was lazy below 3500 as expected but still was fun enough for street car. It woke up abit with 3600 stall. With smaller cam like 503 or 502, it will be much more torquey. The 360 was a 6500 rpm motor. 503 will be done by 6200 or so and 502 cam by 5800 likely. Rough estimates. Both cams are very common in lt1 world as street cams with some bite. 190-200cc isnt too much for a combo like that. You end up with an ls1 car type power band and those cars dont wake up til 3000-3200 in stock or bolt on form

 

I do think alot of guys try to over come the limits of a TPI with larger injectors(more gas) when it's limitation is the air flow at the top end. It's that limitation that you need to keep in mind and to compound a TPI's natural strengths of a good bottom end and middle curve. That would be all on the tune you put on it in the fuel curve/ignition timing.

 

Those ranges of 200 to 230cc really sing 4,000 to 6500 or 7000 with the proper SCR/DCR, cam combo's and cubic inch engines. What gets complicated is when you aren't mind full of the attributes of the combo your working on. I.E. a relative small c.i. engine with a TPI,and the power curves they operate in. I do think the trade offs are more in play.

This being a heavy street car(needing as much torque as he can mustard) with decent gears,with a steep first to second gear change, and where on the street where torque is king.

 

So it seems i would have been better of with the 503 cam and 185s?

 

Man,I'm not knocking your deal on those heads. Just wanted you to know what your getting if you decided to buy them. It doesn't change no matter what you do. There are always trade offs. Orr is giving you good advise too. Just the other side of the coin so to speak.

 

Hsr is holley stealth ram, a shorter runner tunnel ram type setup. Its not limited to short tpi ranges.

I tend to think ppl make too big of a deal with "low end" power/torque on street cars. 200 cc when cammed right will still make alot of torque. I dont consider a 3500 lb car with driver to be that heavy and with that you dont need much torque. My ls1 car is 3686 lbs with me and even with 2.73 gears and 3200 stall, it flys thru gears and thats only 320 lb ft at tires but its a broad flat torque curve with smooth rising hp curve. I think that makes a great street car. Tooo much instant torque and you can have traction issues and thats not fun. Ls1 car didnt start making good torque til 3000's rpm. It would dead hook on street tires full throttle from dig with 2.73's and stock converter but soon as it got to 3000 it broke loose. Now you have 2800 stall and lots of gear. Peak torque falling in the mid high 3000's range will leave you with acceptable power levels below peak trq to converter rpm and also flat curve way past 5000 rpm where hp starts to take over at 5252.

Short runner intake makes broad power curve. Look at lt1 and ls1's. A good 350 motor should have atleast a 180 cc head operating to 6000 rpm but many really do well with the 190/200 cc heads with medium cams and still drive well. Loads of guys here running similar combos and even with tpi intakes which dont alllow as much rpm.

A good head is more than just cc size, keep that in mind. Velocity profiles are very important. Generally a good street head has higher velocities designed for lower rpm ranges. More flow per valve area is a good way to tell when comparing similar heads but really you need the port velocities at various positions to see how well air is flowing.

Just my opinion and experiences. I would not hesitate to run your combo. Small cams with larger heads have worked well in alot of motors. I think a higher lift faster cam lobe in similar duration on tighter lsa would work better and id have heads to bump compression closer to 10 to 1. Faster valve motion is tougher on springs but you can get better cyl fill at lower to mid range rpms for that torque. Xe's with 1.6 rockers do make good power tho.

 

I think the bolded area describes my motor. 195cc head, .015" head gaskets to raise compression a bit, not a big cam 236@ 0.050" .550" lift 110 LSA. Mine is carbed, but with a Vic Jr. intake which does kill off some low rpm torque. And I'm a stick car so that can bog the motor down at low rpm easier than a auto. Plus the OP has slightly better gearing than I do out back. I still have no problem completely blowing the tires off from a 5 mph roll or a 40 mph roll. At 5 mph, I'm pretty much just letting the motor idle while in gear. Ran a max of 111.83 mph in the quarter and assuming a weight of 3400 pounds, the online caculators put it at 465 hp at the crank assuming a 20% drivetrain loss. And I haven't even played with the carb yet so there may be more power left. Drives very easy on the street, even under 2000 rpm while cruising. I have absolutely no desire to have any more torque down low in the rpm's. And it pulls hard to 6400.

 

Thanks guys . Im going to save the 502 cam and buy the 503 or maybe something with a lower lsa and some 1.6's and run the 200cc heads I already bought and see how it goes.I dont want shave the heads in case i ever add a power adder like a procharger .(when i get bored with it again) Im sure it will be much better than my current setup. Thanks for the help

 

All those summit heads are the same castings as trick flows 23deg. head, made by them (owned by summit) I wonder if they really are the 195cc TFS head. I doubt they would make a new casting for a 200cc head

 

They used to be trickflow since i believe summit owns trickflow but last i heard they are brodix ik heads.

 

I have 195's with a 226/234 .565/.565 @.50 and a Miniram stock bore, with the stock converter it was a dog until 3400-3500rpm, but it would still burn the tires from a dead stop on the street with street tires, I now have a 3400 stall and to be honest I could drive it everyday if it wasn't for the lumpy idle, but I have to be real eazy on the throttle cause it will ignite the tires.

 

Orr-all due respect. You guys all the time talk about small radial tire racing and how hard you hook them. The idea of not building in as much torque as you can into a street car because you can't now hook the car is confusing. Torque is what presses the flesh against the seat. Not being able to hook the car is the next leakiest link that is a whole other issue. It is also the most common rpm range he is going to use and enjoy. Honestly count how many times over the last yr have you on the street buzzed the car to even 5500??. I'm just saying.........

 

Theres a difference between running a small tire slick or dot radial at the track versus a belted street tire on unprepped streets.

My old turbo cars response was violent and blew tires off in 3rd gear from 50 mph rolls. My new combo outpowers the old but the response and the torque curves are completely different. I can hook in first gear on my lower boost levels on the street.

Too much torque doesnt make the faster car. Hp does. Trading off lower rpm torque for higher rpm torq which means more hp at higher rpms makes the car more fun in my opinion. If you cant enjoy the car on the street because it simply roasts tires then what good is it?

The last question you ask, in my normal daily driver i dont really beat on it. Sometimes but rarely i need to take it over 3200. But the camaro is in boost majority of the time . I didnt build it to look at it

 

Brodix IK heads used to be Jegs. Jegs has now switched to Profiler. Summit uses Trickflow.