Hey Guys,

The current 350 in my 68 camaro is a good driver, but doesn't have the performance I'm looking for. So I bought a set of 462 casting heads from a buddy and started my first port job.

After removing the valve springs I checked all the seats and ports and didn't see any cracks or scarring. Especially in the middle of the heads by the two exhaust ports.

I spent about 8 hours last night port matching the intake and exhaust. Most of this time was spent working on the exhaust shape and cleaning up the intake. I took them to a local machine shop and they said I did a good job, just need to go back and shape the ports a little different to get better swirl with the smaller valves (195 or 196 I think)


I'm looking to build a high revving street motor with about 400-425 HP that runs on pump gas and is dependable. I'd like for it to have a good sounding and performing cam, but one that is streetable.

What do you guys reccomend for rocker/valve/valve spring setup?

I'm guessing I need to go with roller rockers and stainless valves. The springs on them now are dual springs from comp cams I think.

I'm still learning, so I need to understand how lifters affect everything. I understand that hydralic lifters keep pressure against the rocker at near 0 degree lash but I need to learn more about rockers etc.

Please hunt up Butch, (aka, trmnatr) on the sites and ask him what to do??

Please tell him ol' pdq67 sent you asking and he's a great guy by me!

This should hook you two up??

http://www.chevelles.com/forums/showthread.php?t=239711

pdq67

Call and ask about the VooDoo cams and get a cam kit.

i can tell you from past experiance that a comp magnum 292h (if you want hydraullic)
with those 186 heads on a 350 will make 400hp.

with a 4 speed and 3.55 gears... it will pin you in the seat everytime..

10 to 1 and you can run pump gas all day long..

or, call UD Harold from teamchevelle.com to have him come up with something.
he just made a cam for me. i get to test drive tomorrow.. so i'll be posting with results.

Aaron

He, He!!

YOU CAN'T GO WRONG W/ A UDHAROLD CAM by me!!

pdq67

Thanks for the info guys. I spent the last 10 years building turbo/Nos VW engines so some of the basic technology is the same.

Just wished I would have gotten into SBC's back then.

I'm going to do more research, but it seems like a roller rocker setup may be the way to go. I like a high revving engine.

The only way to describe it would be the way a late model dirt car revs/sounds. I had a 65 Nova with a built 327 and I want to replicate the rev with the new 355.

My understanding is that roller rockers will allow more agressive cam profiles, reduce drag/friction, and allow the engine to rev higher than the "Flat tappet" rockers. (I'm guess that is what you call it. I has a flat spot that is actuated by the valve)


Now I have to do a LOT more reading to see if I messed up the ports in my 462 heads. I did a lot of shaping around the sides of the valve guides and grinded the ridge out of the intake port 1/4" under the intake seat.

Now I'm going back to read about shaping the ports for swirl and velocity based on the type of engine I want to build.

I wish I could find a copy of the old grumpy jenkins book on porting heads but I can't find info on it. OR, a good link that shows details on porting the double humps.

As a former owner of a dirt late model I can tell you that part of the reason you can rev them so quick is the small multipul disc clutches or clutchless Bert transmissions in some cases allow them to rev really quick. Of course neither of those setups would last very long on the street. One way you can get a similar efect would be to use an aluminum flywheel & 10 1/2" clutch assuming you're planning on running a standard transmission. Big bore & short stroke like they did with the Z/28 302 engines is also a serious RPM engine. One combo we played with back in the circle track racing days was a 400 block with a large journal 327 crank using bearing spacers & custom pistons. Comes out to a 348 with a stock bore or a 354 if it's bored .030 over. That combo is a bit expensive since the pistons have to be custom ordered but it will run 8000 RPM all day long... Amazon.com has the Grumpy books used for 57 bucks.. Kinda pricy but worth every penny. I'm glad I bought mine a million years ago when they were $14.95 Amazon.com: Chevrolet Racing Engine: Bill Jenkins: Books

Quote - NHBandit One way you can get a similar efect would be to use an aluminum flywheel & 10 1/2" clutch assuming you're planning on running a standard transmission. Big bore & short stroke like they did with the Z/28 302 engines is also a serious RPM engine

A road race -Z/28 style powerband is what I'm looking for. The last 327 I had was built with alum flywheel and 10 1/2" clutch. It didn't sound exactly like a dirt car, but you get the idea. You pull the engine up to about 3k and then hit it. It seemed to rev about as fast as I pushed the pedal. So I guess the point is it was very responsive.

I bought the comp cams rod balancer so I'm going to try that as well. Going to have my crank checked out and turned 10/10. If needed I will get a better crank and rods but I'm trying to build on a budget since it's my first engine to build myself.

I thought about that thumper or mutha thumper cam/valvetrain but I haven't done research on it.

More than likely I'll just get a new cam, stainless valves, springs, retainers, seals, and have the heads slightly decked or surfaced.

I bought some of the plastigage and I want to check bearing clearances just to be safe.

Hopefully it will make some good power. I'll blow it up and build another one. Or at least I hear that is how it goes :)

Here is the casting numbers on the heads I am working on
Under the valve cover on top of the head. They don't have acessory bolt holes.
8890462
H 2 6
T
GM1


The bottom of the heads on the intake ports read 3C and 462

After looking again. The # is 3890462

you can run the 327 crank in a 400 block and build it with 6.125 rods and you are about .10 in the hole but man what power and it will hold 8300 for an entire race season.

now i have went the other way we built a 305 with a 400 crank it worked out to be a 329 ci its an awsome lil motor for street stock dirt class

Heck, stock rockers will go above 8,000 rpm so consider it!

My old '55, 265 P/U motor head's rockers would go above 7,500 as long as my points held on!

He, He!!

pdq67

I would change your 350 idea. The 350 is not known as a high winding engine. A 327 or a 302 crankshaft and pistons, will go right in a 350. All are 4" bore engines. The other high winder that is popular in dirt modifieds, is the 377. Those heads even ported, are too small for a 377, so I would think about a 327.

I would change your 350 idea. The 350 is not known as a high winding engine. A 327 or a 302 crankshaft and pistons, will go right in a 350. All are 4" bore engines. The other high winder that is popular in dirt modifieds, is the 377. Those heads even ported, are too small for a 377, so I would think about a 327.

Hmm..

The 462 heads I'm working with came off a complete 327 4 bolt main I bought from a friend.

So it may be a good idea to build the 327 I already have and pull out the 350 from the car.

Question: Are the 327 and 350 blocks the same? I know they both have 4" bore. But a 327 would have shorter stroke right?

The guy I bought the engine from kept saying they are 327 heads, but a 462 is a 4" cylinder head so its the same right?

all generation I sbc heads will interchange except for the old 265's...I believe. So yeah they are the same.
Sounds like you know where your headed....

I bought my car as an SS 350, but it's not documented so I might as well build a hot little 327 for it. The 350 in the car is stock and doesn't match #'s so it's not like I'm going to decrease the value of the car.

It doesn't have a TH350 in it, and I'd much rather have a 4-spd with a high revving road race style engine. So I may end up selling my 68 and buying a project car to build how I want. I like the Z-28 stance.

All of this changed when I bought a 95 trans-am 6 speed. I really like the way that car pulls out and would like to replicate that "feel" to a certain extent with my 68. I'm sure it will require a lot of suspension work so I'd rather start with a project than rebuild a 90% finished car.

Those heads as stated will bolt on to almost any small block. They were designed to be used mainly on 327's. I really don't know how well they are going to flow after you have ported them. In the stock form those intake ports were only about 160 cc's. If you can, have them flow tested and see what you get ! I have always been curious how well the 461 or 2's would flow after being ported ! Your newer Camaro is quick mainly because of the gearing, and the fuel injection maps ! I believe this engine is the LT-1. This engine is not a high winder, and they are built for the low end ! Street cars don't need to go above 5,000 RPM ! Also with the double over-drive, I can't imagine how fast you would be going at 8,000 RPM !

Why would a 377 rpm any better or any more the a 350? Same stroke crank just one has 4.00 bore and the other a 4.125 bore(heavier pistons to boot). A 355 properly built and internally balance should have no problems turning big rpms. My 383 with a 3.75 stroke crank runs 7000-7200 with no problem and my builder who is a dirt track guy said it would go 8000 no problem if I wanted to. Really do you need more than 7000 on the street? A SB at that rpm is still pretty awesome sounding!:) Just my .02 worth!

This is getting out of my knowledge ball park, but it has to do with the bore X stroke ratio. This is why the 302 was such a screamer ! Some one with more knowledge in this area, please chime in ! That is also why a 348 as mentioned would also scream ! A 377 will out RPM a 383 the same as a 327 will out RPM a 350 !

Note: I should clarify that by out RPM, I mean out perform. Rpm faster etc.

8,000 RPM is still 8,000 RPM !