Advice on engine build

[mr_han_solo]

Hello,

I am wanting to build a 350CI Gen1 Small Block Chevy for my 280Z SCCA car. Now I have been through the rule book and realize that this engine will put me in a totally different class where I will have to spend a lot of time and money to ever be competitive. However, after reading some things this seems to be a swap that a lot of people do. My plan is to build the engine and mate it to a built t-5 transmission. I am a college student, so this is something I am trying to do on a low budget per the winter. Honestly, I know that I am going to be investing some money in this project so I am prepared for that aspect of things, I just don't want it to get out of control.

As for the engine I already have the four bolt main block. As I previously stated my goal is to build this engine for SCCA as the 280 is my SCCA car. In my mind I'm wanting to do a DZ302 homage with the 350. I am already looking into a cross ram setup, and as my primary goal is autocross and club racing, I am wanting something that makes power in the high rpm range. However, I also want to be able to drive the car to the events so running on 93 octane is a must. I have purchased several books (How to hotrod your small block, how to rebuild a small block, smokey yunick's power secrets, etc.) and have been reading them to familiarize myself with this project.

As I previously stated I already have a block and a forged crank. I have been looking at some heads and that's where my questions come in. The heads I'm looking at are aluminum (to keep weight down) and made by Procomp. Now I know that I'm going to get some crap for going with the cheap pro comp heads. I've done a ton of reading on them and read that some people hate them and others like them. Is it the cheap route? Yes. However, I have talked to a (fairly) local guy who does head work and he assures me that he has worked on pro comps before and can get some pretty good flow numbers out of them. I have checked with some references and I do trust his word. That said, I am lost on intake runner size. Pro comp offers them in 190, 200, and 210 sizes. I have already settled on getting the angled plugs over the straight. I'm just needing to know what intake runner size is best for my build. Hoping someone here can help me out.

Thanks,

Han

[Robftw]

Angle plugs, 190cc if you are keeping it around 350-355ci you want the velocity from a smaller runner.

 

as for intake don't bother with a crossram or tunnelram for autocross. Super victor or victor junior will be the way to go

 

If you're building a high rpm motor make sure you get a 7qt oil pan with baffle plates and a windage tray

[rsicard]

Don't cheap out on the cylinder heads.  Get the AFR-195 CNC'd cylinder heads.  They will have good velocity and perform better than all others.  Go to KMJ to get the 7 quart oil pan with baffles.   They have one with 7 inch depth.  Recommend SRP professional pistons of lighter weight and longer connecting rods yielding less reciprocating weight and internal balance the crank, rods and pistons.

[surpip]

It would be a waste to destroke that 350 with a 327 crank, IMO I would go for a 383 you will love the low end Tq and even on a budget still get them to rev to 6500 without much effort. I wouldn’t go any less than the 350. Bore it .030 get a decent piston (JE, SRP) good rod and a lightweight crank and as long as your cam and vavetrain can handle it you’ll be turning up to 8000. As far as heads go it really depends on what you decide with your bottom end.

Edited August 20, 2013 by surpip

[mr_han_solo]

It's going to be a 350. I'm going to go with 190cc runners in an aluminum head. I'm still looking at options there. I have looked at some threads of people that did similar engine builds and i'm also looking at going with this cam:

 

crane solid lifter 110921 cam
http://www.summitracing.com/parts/crn-110921

 

Any thoughts on that?

[rsicard]

Purchase and read book authored by David Vizard.  Especially articles on squish and quench and space between the piston tops and cylinder heads.  For a solid lifter cam use plenty of ZDDP additive in the oil.  Buy two sets of valve springs, one weaker set for break-in, the other for after cam/lifter break-in.  Have the crankshaft thoroughly checked.  Line hone the main bearing bores and install ARP studs.  Also use ARP studs for the cylinder heads.  Get the block near zero-decked.  Good squish and quench will fight off pre-ignition and allow lower octane gasoline.  Pay attention to David Vizards recommendations.  He has a wealth of experience.  He does something and then TESTS to see what the results are.

[surpip]

I would recommend a solid roller as opposed to the flat tappet easier break in and you don’t have to worry about high zinc oil. Plus you can get a more aggressive cam profile but no matter what you do don’t cheap out on parts, save up to get the stuff you want not what you can afford at the time.

 

[skirkland1980]

A roller cam setup is way expensive. A hydraulic flat tappet will work fine. The procomp heads will be fine they'll just have a very unfinished appearance. You'll need to smooth out the runners and combustion chambers, especially the bowl and seat area. If this disinterests you, use a better head. Don't take stroke out, add stroke if possible. 350cid 190-200cc, 383 210+. Have fun!

[310z]

I will have to second or third the David Vizard books. Pick one of his builds and follow it. I built a 383 following his build and put it in an old heavy ski boat. It is pretty impressive. Not having a matched set up that is proven to work well together tends to cost a lot more in the long run. Especially when you are not satisfied with the results and are constantly buying and changing parts.

[mr_han_solo]

Well I realized that there is not need to drop a ton of money on aluminum heads when all I have to gain with this is a loss of 50 lbs. Instead I have been scouring the local car yards looking for 062 L31 Vortec Heads. Now if I go with a crossram I will have to modify the heads for the intake, but from everything I have read these heads are plenty good for what I'm wanting to do. I have bought a set of lt1 (1993-1996) powdered metal connecting rods. So it's starting to come together. What Vizard book has the list of builds in it? "How to build max performance Chevy small blocks on a Budget" or "How to build horsepower"? I already own his "How to rebuild and modify your small block Chevy."

Edited August 27, 2013 by mr_han_solo

[310z]

They are both full of information you need. The title to the book that has different motors with build specks is (How to build Chevy Small Blocks on a budget, By David Vizard ) I built a close copy of #8 except I used Dart Iron Eagles heads and did the port and bowel work myself. I used Scat 6 in. rods and a Scat steel crank .

[mr_han_solo]

I went ahead and bought the Vizard book. In the meantime I plugged my build into Desktop Dyno 2003 to get a general idea of where I would be at. I used the previously mentioned Crane 110921. However, I don't really like what I see on it. I was wondering though, does this think look right? Should I have that much torque that low in the RPM range?

 

With Crossram:

 

With Victor/Victor Jr. Style:

 

If anyone has any other cam or grinds that I can plug in, I will be more than happy with any suggestions. I really have no idea what to look for in a camshaft.

Edited August 27, 2013 by mr_han_solo

[Robftw]

Run a single pattern cam, they always. ALWAYS will make more torque and have a much better curve in relation to horse power.

 

Try this:
 

Intake Duration at 050 inch Lift: 254

Exhaust Duration at 050 inch Lift: 254

Duration at 050 inch Lift: 254 int./254 exh.

Advertised Intake Duration: 288

Advertised Exhaust Duration: 288

Advertised Duration: 288 int./288 exh.

Intake Valve Lift with Factory Rocker Arm Ratio: 0.525 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.525 in.

Valve Lift with Factory Rocker Arm Ratio: 0.525 int./0.525 exh.

Lobe Separation (degrees): 108

http://www.summitracing.com/parts/isk-201035/overview/

 

 

this was my old 355, it was a really modest build with a 700r4 powering the car, this is the type of curve you should see

This is a wheel horsepower dyno, so assume an additional 70 hp to the crank, the cam was 270 duration and .485 lift

Edited August 27, 2013 by Robftw

[mr_han_solo]

Okay, I went ahead and got a set of bare ProComp heads. I talked to some other people that have bought the new 190CC castings and they said that they were excellent compared to what they read on the internet. I have also decided on using the Competition Cams 12-224-4.

 

Now I am trying to get the parts to build my heads. I am wanting a high revving engine, and I have found a pretty good deal on some competition parts. I just wanted to check and make sure they will work together with my heads and my cam.

 

Valve Springs:

 

PSI 1.310 Chrome Silicone Valve Springs 350 @ 1.500" ID: .645 Seat Load: 225@ 1.750 Open Load: 350 @ 1.500 Coil Bind 1.150

 

Retainers:

 

Xceldyne Mini Top Lock Titanium Retainers 1.250" Outside Diameter 2nd step is .955" and the locator is .655".  The hole at the top measures close to: .375", the bottom hole measures .325".

 

Locks:

 

Del West 7MM Titanium MINI Valve Top Locks

 

I have been doing some reading and I am concerned about the pounds of the spring and the wear on the cam. I got my David Vizard book in and after reading it, it states that anything between 240Lbs and 250lbs should be good for 100,000 miles.

 

Also, I am also concerned about these locks working with standard Manley valves. I could also get some titanium valves for pretty cheap, but I have read that I will have to have my heads machined and I don't want to go that route. I'm looking at just getting Manley Race-Flo valves. Can someone tell me how to calculate if I will need valves that are .100 longer?

[Robftw]

For the valves take them to the machine shop and show them your parts, they will most likely measure it for free and let you know what size you need.

You should get some 1.3 rockers for break in if you don't feel like removing springs during initial start up

[mr_han_solo]

I really don't want to spend $200 for a set of rockers that I would only use during break in. Instead of taking the inner springs out, could I just use stock springs (which should be lower pressure) and just install my actual springs after break in?

[Robftw]

I've never done it that way before, the coil could bind.

 

Are they dual valve springs? Just take the smaller one out if you have the tools and keep it under 2500 rpm