[Jimmy Neutron]

Hi

I´m rebuilding the motor from my 1970 Camaro.
What do you think about this combination? How much HP will the motor produce?


350 4Bolt 0.30
Eagle cast crank
Eagle I rods
Pistons:Flat-Top TRW-L2256F30
Cam:234/244 SUM-1107
Manifold:Weiand Stealth
Heads:GM double-Hump 64cc (casting 492)
carb: 600 Edelbrock
Transmission:TH 350 B&M 2400 stall
Rearend:8.5 10 Bolt with 4.10 Gears
Tires:255/60 R15

 

[Max Keith]

what do I think?

I hope you have a posi rear end. Other wise your rear tires are going to go up in smoke.

I would go with a cam thats about 10 degrees smaller on both intake and exhaust, and drop down to a 2000 rpm stall. You will have a lot better driveability with it.

Are you planning any porting work on the heads? The reason I ask that is that I have concerns about the stock heads being able to supply the flow that your chosen cam will require.

 

[Jimmy Neutron]

Yes I have a posi rear end.

I plan porting the heads. But I have never done it bevor .
I have read some artikels about porting.
Can you give me some good advise about porting?

The car is only for weekand and strip use.

 

[Max Keith]

head porting

Head porting is pretty much a science. You dont want to go in and just start hogging out metal. I would recommend finding some good articles on your heads and find out where to do the most work on them and what to leave alone.
My main stock in trade is Ford engines, so I am not going to try to explain how to work on a Chevy head as the runners are different. I could look at a head and see what needs to be done but that is very difficult to do looking at a pc screen.
I have seen several good articles on home porting.

 

[HemmiGremmie]

Ditto on the cam.
Be careful the dbl hump heads havent been shaved to much or you may have detonation problems with regular gas. HG

 

[willowbilly3]

Don't forget to put hard seats in those old heads. Actually there are a lot better heads out there. For cheap I would get a set of the small chamber 305 H.O. heads. They have a very good runner design and even with 1.94 intakes and a 3 angle valve job you can get them ready to go for under $500. Another good choice is the vortec heads. Cheap and plentiful but will require a little modifying on the intake holes. Either way I don't think those old heads have all the mounting holes you need for your accessorys.
Also I would call a cam techline, like Comp Cams. Tell them what you are doing and they will point you to the right cam. They are the pro's and that's all they do.

 

[68chevelle_ss]

I had an engine very much like the one you're stating. Mine was in a chevelle and was a grenade engine but ran decent for a little while. I had the double hump heads, stealth weiand, 4.10 gear, 230/230 @ .050 cam, 600 edelbrock carb, and a 3600 stall converter. My heads didn't have the acessory holes either but I bought the March alternator bracket for use with that type head. Let me know if you stick with those heads and would be interested in the brackets.

 

[Jimmy Neutron]

My heads are from 1970 and have the acessory holes.
I think they are Lt1 heads.

@ 68chevelle_ss
Did you have driveability problems with your
combination?
Had you ported the heads?

 

[68chevelle_ss]

JimmyN, As for the double hump heads...I did have them port matched to the intake which is something you can do at home. If I ever port a head beyond that I will take it to someone with experience and a lot of it. I now have a BBC and the heads were ported by the previous owner who was suppposed to be a knowlegde head man. Turns out he ported an exhaust port right into a coolant passage. Now that's a pain. Just get an engine in the car...fire it up...and see water coming out the exhaust. Very discouraging.

As for driveability...I would say no if you don't mind turning a few rpm's on the highway. That's my only negative comment about the combo was/is the rear gear and highway driving. At 70mph I'll turn around 3500rpm. There's been threads started here on that very subject but I do like that gear at the track. As for the cam no problems, but then again I like to hear it lope at idle.

Let me know if you have any other questions.

 

[Elevinpointsixtoone]

I think I would put a double pumper on there. Maybe a 700 or 750 CFM if you want peak HP. Your rear end gears and compression will get your R's up quick enough. The 600 will just cut you off at about 5500 RPM I would gestimate.
Otherwise go smoke some rubber!

 

[Mighty Mouse S-10]

Dito on the bigger carburator. With the big cam and ported heads with big valves a 600 is to small. You don't want to have it nose over at 5000 and run out of air after spending all that money.

 

[Max Keith]

carb choices

Your 350 definately wont nose over at 5000 RPM with a 600 CFM carb. I have a 600 vacuum secondary Holley on my Twisted Wedge headed 351 W, and its made excellent HP all the way past 7000 RPM,and it has been as high as the peg bending on the tack at 8000 RPm, has never flattened out on me either, and thats with a 230/235 degree, .510/.515" lift solid lifter cam, and 9.4:1 compression, with an Edelbrock Performer intake.
Whether you go larger or not is not my concern, but I would recommend going with a vacuum secondary carb, especially with automatic and in a 3400 lb (estimate weight) vehicle. I would tune the secondaries to start to open at about 3000 rpm on a 700 or 750 either one.
I have a C-4 behind my 351 with a stock converter and it stalls at 2200 rpm.
This was with a 2700 lb car and 5.14:1 gears.

My engine, on a real dyno pulled 398 peak hp at 5500 RPM, with 1 5/8ths primaries, and closed exhaust. And was putting out 342 HP at 7000 RPM. A test with a 750 cfm, only netted me 3 peak hp and it still peaked at 5500 RPM.