Hey guys,

To start this is my first engine build and Ive been doing alot of research but their is a few questions I have to help me clear everything before i buy it all. I'm building my Gen 1 350 Small block, from what I have read its a 4 bolt main with a 2 piece rear main seal, casting # 10066036. The car has a Edlebrock ported intake manifold and Headers, Holley 650cfm Double Pump Carb, I plan on getting new heads and a cam. I plan on getting a set of Dart (127121) Heads and then getting COMP Cams Magnum Rocker Arm and High Energy Pushrod Kits (RP1418-16) along with the necessary studs and adjusting nuts. For Cams theirs three different Xtreme Energy Cams from comp cams I am looking at which I will list at the bottom of this with the heads and other parts links. My problem is I don't know which one I can use each one is increasingly a higher lift. And of course I want the one with the most list but I'm just getting confused on if these heads springs and rockers can take it. If some one could shed some light on this for me that be awesome. I also do plan on getting a 3000 Stall converter. Thank You for your guys help !

Dart Heads -
Dart 127121 SHP 180CC Assembled Engine Cylinder Head-Small Block Chevy - Speedway Motors, America's Oldest Speed Shop

Stall Converter -
1965-91 GM TH400 Performance Torque Converter, 2700-3000 Stall - Speedway Motors, America's Oldest Speed Shop

Cam 1 -
12-242-2 - XTREME Energy

Cam 2-
12-246-3 - XTREME Energy

Cam 3-
12-250-3 - XTREME Energy

 

Heres my concerns on making a good choice for this motor.

Is this 350 a completely stock block? is it bored out?

The heads you posted are basically stock heads... The only benefit I get of these dart heads are they may flow a little better...However, for your Model year of motor.... I believe they have the same valves as your stock heads...

Heres a suggestion..
I would look more into the corvette style "Camel Hump" heads from the same model year or earlier.... The intake valves are 202's and the exhaust valves are 190's.. talk about a high flow head! These were used on the the 327/375 hp fuel injected and non fuel injected models.

As far as a cam shaft... Comp Cams are are Great Cams.... Since you don't have a bullt up lower end.. (that's what Im guessing you have) I would contact Comp cams and see what the recommendation would be for a stock block to get the most out of it. Which will be a mild Cam.. Not wild...lol
Which is fine ...Youd be surprised at the performance gains! also I don't know if you read thoroughly about the cams they offer..there maybe some Machineing involved as well as some other issues that I'm not sure is meant for beginner builders like yourself... That's also mentioned at the bottom of the page of the cams you listed. So, I cant recommend what cam is right for you.... That's why calling Comp Cams is the best recommendation I can give you.

The next question is...
I'm guessing your going with Hydraulics as far as lifters? or were you planning on going with mechanical? If your going with Hydraulic lifters and cam setup(which were the numbers from the cams you listed) I would go with a 1.5 roller rockers vs the old style ball rockers... and be sure.... That the rocker studs are screwed in.."NOT" pressed in. Pressed in rocker studs will never hold up the rpms or the pounding of a performance cam shaft. They will actually pull the stud out of the head over time...

I hope this answers your concerns...
Please keep us informed on how the build goes and what you decided to go with!

 

Block is stock not bored out, I planed on doing hydraulic lifters. Thanks for the help do you have a link or model type on the heads you suggest I look for ? Also I will get in contact with Comp Cams and see if they can help me.

 

I'm not familiar with any shops in your area...
I'm in Michigan...lol However, The trick is to finding these heads is contact an actual race shop and see if they can point you in the right direction... You may even get lucky by checking with your local wrecking yard, pull apart junkyard.. ( I dont know what there called in your area)

What I do know,
Is these style heads area widely used/desirable in drag and circle track motors. So if you have any of these kind of shops in your area..check with them as well.

Good Luck!
keep us appraised of your Progress!
Thanks for being a MCF Family member!

 

I Do have a shop I have been talking to and they offered me a set of ZZ4 heads, only had 500 miles on them and I own a set of 1.5 scorpion roller rockers, but he has 1.6 that he is looking to sell. Would these be a good solution ?
http://www.summitracing.com/parts/na...Feg-MgodRwkAMw

 

1.6's will help to increase the lift on either a stock or mild cam...

If there used...
It would depend on how much and what application he was using them for.
Besure they don't have any unusual wear marking and hope fully the roller bearing in them are still round and unbroken. They should feel as smooth as glass!(the bearings) at the ends and the pivot points. anything less and there not worth it used...

1 more point of interest:
If they are pressed in stud'd heads.... Be sure the studs are pinned!

 

Those Dart heads will flow much better then the 'camel hump' heads. They also come with screw-in studs and guide plates - something you will want. The 'camel hump' heads also have a risen intake port that may be a problem if you need to enlarge the spring seats (which you'd probably have to do). By the time you buy the heads and have all the machining done to them you'll have as much (or more) into them as the cost of the Dart heads.

Most people seek the 'camel hump' heads for restoration projects and the price of them can become astronomical. If I were to use a pair of OE heads I'd look for a pair of Vortex...they put the 'camel hump' heads to shame.

David made a good suggestion - contact Comp Cam and discuss your build with them. They can recommend a cam that will be compatible with your other performance parts. They also have info on their web site about cam selection or you can download a program to help you decide on camshaft selection. If you want to save a couple of bucks you may want to consider getting one of their kits which includes cam, lifters, springs, retainers, locks, stem seals and timing chain set. A pair of bare Dart heads, a cam kit and some sodium filled valves should be right in the ballpark of the assembled Dart heads.

Edit: As far as rocker arms go, the ratio is dependent upon the lift of the cam, type of piston used (domed, flat top or dished) and the stroke of the engine.

 

After talking to Comp Cam's and my local shop this is what I bought.

Comp Cam Xtreme Energy Cam XE268H -
http://www.summitracing.com/parts/cc...42-2/overview/
Its a Hydraulic Flat Tappet, it was recommended from the Comp Cam Rep

1.52 Rockers and Chromoly Push rods-
http://www.summitracing.com/parts/cc...2-16/overview/

Heads-
Dart 127121 Heads
Dart 127121 SHP 180CC Assembled Engine Cylinder Head-Small Block Chevy - Speedway Motors, America's Oldest Speed Shop

Out of the 4 heads I told him, He suggested these heads because this will increase the stock compression to about 9.4.1 and for a couple other reasons, including max lift, and said that 180cc runners was the best for this cam.

Torque Converter w/ 2000-2200 stall-
1968-81 GM TH350-TH400 Performance Torque Converter, 2000-2200 Stall - Speedway Motors, America's Oldest Speed Shop

The cam I went with was the biggest for the stock converter, but after talking with the rep, explaining this was a street/strip application car.. and that it will be weekend/nice day driver, and that I wanted to do my local points races he recommend that I upgraded to a 2000+ stall converter.

I also bought a lot of other things.. gaskets, some tools, a patch panel, a full weather stripping kit, a new headliner, window motor, switch, my car has a 70s z28 style hood on it ... don't know how or why so I bought the stock hood and some more stuff that I just cant remember right now but it all came out to about 2K...

Buyers Remorse No, Do I want to get Drunk tonight yes.

 

Hey guys, needed a little more advice..

With all the extra heat coming I wanted to run a 160 thermostat so I am trying to figure out if the stock radiator will do with a upgraded fan like flex a lite or even electric fans ?

 

The stock radiator will be fine with that 268 cam, as long as it is in decent shape, I know quite a few people running basically your same combo without issues.
The stock fan will be ok too, but an electric fan would be handy at the strip.