My winter project for the '79 is going to be a new 427 small block to replace the 383 I blew up. Looking for advice on cylinder head selection. Definitely aluminum. Sounds like I'm going to need something in the 230 cc range. I will also need angle plugs to clear my headers. Some advice on cam selection would be welcome too. I will probably go with a Comp Cams retrofit hydraulic roller since I already have the lifters.

 

You have a couple choices in the 235-245 cc off the shelf but most need a shaft rocker or very least an offset rocker. I would call Chad Speir too. He has some bigger ported heads that offer the velocity/cross section needed for that kind of cubes.

 

Hey drwet, I'm planning for a 427 SBC as well, just not for this winter quite yet. This is for street use, with occasional road racing on a track.
I'm thinking:
- SHP Dart block kit
(18cc dished & forged pistons, 4340 6" rods, 4340 balanced forged crankshaft, balanced flywheel, 2-piece rear main seal)
- Trick Flow® Super 23® 230 Cylinder Heads for Small Block Chevrolet TFS-3241T002-C03
(2.08in intake valves, 1.60in exhaust valves, 0.68in max valve lift, 70cc combustion chamber, 230cc intake runner, 78cc exhaust runner, 420lbs spring good for hydraulic lifters)
- 10.02:1 static compression ratio for 92 octane gas
- Intake manifold: maybe Dual plane Weiand Speed Warrior 8501
(high rise hood)
- EFI kit: FiTech Go EFI System with Fuel Command Center, or equivalent
- 92 octane pump gas
- Tremec TKO 600 - 5 speed manual transmission with 2.87, 1.89, 1.28, 1.00, 0.64 gears
- 3.55 rear differential
- Doug's Headers with side pipes
(1 7/8" primary tubes, 4" collector, catalytic converters)
- focus on low- and mid-range torque, good vacuum for EFI, don't care about high rpms.
- 1.5 ratio, roller rocker arms (maybe CompCam Ultra Pro Magnum 1605-16)
- retrofit hydraulic roller camshaft and lifters
I bought the DeskTopDyno5 software to try and figure out the best cam numbers and so far this is what I came up with, but consider that I'm a rookie:
* Intake: 0.537" max valve lift, 260 seat-to-seat duration, 230 duration @ 0.050", 111.0 intake centerline
* Exhaust: 0.533" max valve lift, 266 seat-to-seat duration, 236 duration @ 0.050", 113.0 exhaust centerline
* 112.0 lobe centerline
* 4.04 acceleration rate
According to the software, this results in
- at 2500rpm: 255HP and 536 ft lb (max).
- at 5500rpm: 464HP (max) and 443 ft lb.
Thoughts?

drwet, do you want to focus on street use? low rpm torque? high rpm HP? Are you planning this for an EFI system? Which octane rate?

 

As a longtime owner of 427 and now 434 small blocks

You need cams and heads that can breath. I only have 227 cc but I use higher lift and duration. Like over 250 and 685 intake lift



It is perfectly street friendly even for 2000 mile trips

I had a hot 355 in my Corvette and then I went to a 383 when the Need for Speed one up I went to 427 you can't compare the amount of power you gain

 

Here are a couple of threads that have good debate over head and port sizing. I tend to fall into the same camp as 63Makoand C3Stroker on head size, but lots of good info to consider from most of the contributors.

https://www.corvetteforum.com/forums...ce-builds.html

https://www.corvetteforum.com/forums...7-stroker.html

One thing is certain - with a 427 SBC, you can gopretty big on head size and not lose much down low - I personally think the size question really boils down to how high you want to rev the motor.

Fair warning - you may get opinions all over the place on this (which is fine, I did, and wanted multiple views) but I also got some negative comments in another thread over one my choices too. Don't let that deter you from making up your own mind.

 

I run 225cc ports with 2.100" valves on my 406 with well over 300 cfm @ .650" lift, my max lift. My cam is 248 duration on the intake. I run a Victor Jr with very large runners in it. Manifold is welded on the top to allow it to be ported for a 1207 gasket, 2.280" X 1.380".

There is no lack of bottom and mid range power in this motor and it screams on top to 7500 RPM. It is docile on the street with excellent drivability. When it was in my 80 Vette with 3.08 gears, it could turn the tires to smoke at will.

I say this because there will be people who will tell you to run smaller ports. With 21 more cubes than I have, I would run at least as large of ports as I have, larger if you can afford the shaft rockers the big heads need.

Mike

 

Had my eye on those super 230s also like to see someone try them. Trick flow is a vendor here maybe they will chime in.
They are turning out a nice product these days..


As said you cant put too much head on a 427. Even my 383 runs hard wiht 230s on there. A tad big but low gears, compression etc lets them work;not too much low end to spin tires when you dont want them too, plenty of top end. 427 will be huge everywhere

Edit: Nice features, nothing worse than "touching up" a cnc head only to find theres no metal.

 

Hello, it sounds like many have done their homework here. Others are correct you're going to have so much torque that it will be hard to put down, but that's the fun part.

Cams are a little subjective, so it's usually best to give us a call and we'll discuss what you've had in the past and what kind of behavior you're looking for.

A flat top with normal valve pockets (about 5cc) would net 11.4:1 That's a little stout for pump gas depending on the cam, but there are plenty of piston options out there. Some companies will even let you make "1 change" to one of their shelf stocking piston part numbers for a nominal price with normal custom delivery times.

The exhaust will be critical if the cam is going to have a lot of overlap...you'll want size "Big" from front to back.

The head we'd recommend is the https://www.trickflow.com/parts/tfs-3241t002-c03 . The engine will go together without surprises. Those are set up for hydraulic roller, but have Ti retainers for higher RPM capability.

There's a dyno sheet on the web page and you can see all the parts we put in the heads under the "repair" tab and other parts you would need to put it together under the "suggested parts" tab.

 

Go AFR 220 and up THEY HAVE 80CC EXHAUST ports , use a 3 inch exhaust all the way back . I also suggest you run a Vacuum pump . I installed off set roller 1.6 rockers on teh intakes which are 2.10 valves.

And this suggestion you need to take seriously. Skip White.. My 427 kills it and I cant be happier .. 3rd season on her 7500 miles and many beatings to 7200 rpm ..

 

https://www.corvetteforum.com/forums...ort-block.html

MY ENGINE SPECS 650HP

My 427 build from the bottom up:
Dart SHP block
Milodon 7qt road race oil pan
Milodon diamond stripper windage tray
Calis Dragon Slayer Crank
Skat H-beam's
Probe racing pistons 11:1 forged
AFR competition ported 220 heads w/titanium keepers and locks
AFR plastic single plain titan intake manifold
EZ EFI 2.0 fuel injection system..
MSD full ignition with crank trigger
Kooks 1 7/8 ceramic headers
3" duel mandrel bend exhaust with X-pipe custom made by D&C design... my son Danny:-)
Borla mufflers
march pulley system
22 lb steel billet flywheel
McCloud twin disk clutch
Fluidamper 6 1/4" HB
Custom Cold Air Intake by me:-) D&C design
Custom cam by Strub 611/592 244/248 109 Sep
Morel reto hydraulic lifters
Crain gold race RR's
TKO 600 transmission
SUPER 10 rear end built by trackdog2
18" custom built 2 piece centerline wheels
Willwood big brake system all around
hydroboost braking
rac-n-pinion steering
550 springs up front, 360 composite in back with all Bilstin sport shocks and front and rear sway bars
3" HD Dewitts radiator
DELTA PAG brushless fan w/D&C custom fan shroud
Dewitts 3" heavy duty radiator

https://www.corvetteforum.com/forums...ort-block.html

 

Well....it really depends on if you have the budget to run Jesel or T&D rockers......when you get outside the 230cc realm....the ports are just too big and you have to run a shaft/pedestal rocker arm.

I like these....always have:
http://dartheads.com/dart-product/pro1-23-227cc-cnc/

I would build 421's that made 630 horsepower unstressed with these heads. This was a 4.155 x 3.875 stroke. I did this to pull the rings down for NOS......4.00" stroke stuff has a 1.00 C/D.....this is great for Naturally Aspirated but power adders would get the top ring too hot.

Consequently....the head works very well for 4.00 stroke.....but I suggest going to 4.155 for 434 cubes......anything you can do to further unshroud the Intake valve is beneficial.....

Truth is that big cube small blocks want more cylinder head.....but then you are into 18 degree and big money with lots of headaches for the novice assembler.

All of the aftermarket blocks will cleanup .030 after 4.155 so just do it.

Be advised that you will need a .900 base circle cam to run a roller...

You will love the 434........it is a beast. A woman I know has one in her 69 Z-28 and it is more fun than sex.

Jebby

 

You've obviously given this a lot of thought. I've been running a 383 for 10-15 years but smoked it this summer. I figure things happen for a reason. My reason must be that I need a 427. I'm trying to use as many parts from the 383 as possible. I'll obviously need more cam for the 427 and probably a small base circle as well, but I should be able to use my Comp Cams retro fit hydraulic roller lifters. Also plan to use my Hooker Super Comp headers, Edelbrock Air Gap intake, and Holley 770 Street Avenger. If the heads I choose have 3/8" studs, I can re-use my roller rockers. Its a street engine so torque is more important than HP. I burn premium ( 91 octane) fuel and am shooting for about 10-10.5:1. I already have the TKO-600.

Your dyno numbers from Desktop Dyno seem a little low. I wouldn't think you'd need a 427 to get those kind of numbers.

 

tpi421vette has but enough of those together bet he could tell you within 5-10 exactly what it will put out. a 230@050 cam will be very mild, you may find you want a single plane. Fun to have that issue though, will have crazy amounts of torque. Tire melter

http://dartheads.com/dart-product/pro1-23-227cc-cnc/

in the pic of the intake port are they running a tube for the head bolt there? Offset rockers? Whats the deal with powder metal valve seats vs??
Like the combustion chamber shape, looks like its been updated over thier traditional one they have used forever.

 

I was definitely disappointed with those numbers. The catalytic converters are not helping and that cam is rather conservative, focusing on drivability and decent vacuum for EFI. I could reach significantly higher HP at 6000rpm with more cam lift and duration at the expense of vacuum & lower numbers at 2000-4000rpms where I spend most of my time. It's all about compromising.

Personally I would be worried about a 10.5:1 compression with 91 octane. Maybe you would need serious overlap to reduce the dynamic compression? I would stick around 10.0:1. Again, take everything I write with a big grain of salt, being a novice.

 

How does your EFI like the 109 LSA? EFI systems prefer 112-113 LSAs, right?
Any idea what your HP/torque numbers are at 2000-4000rpms?

 

The Lobe Separation measurement makes it hard to compare cams. The easiest way to gauge idle vacuum will be looking at the intake opening event. You can put them into several of the online "cam timing event" calculators. It allows you to see the actual differences between seemingly much different cams.

5 deg. btdc intake opening will have a noticeable idle, 10 deg. a little more lumpy, but would be fine for a 434 with injection.

You can also look at the closing event. Generally street engines are in the 42 to 50 degree abdc range intake closing. Exhaust opening will be 50 to 60 bbdc. Exhaust closing will range from 2 btdc to 10 atdc commonly depending on overlap desired and is influenced by exhaust backpressure.

These individual events are picked first to determine the duration and resulting lobe separation and advance.

 

The guy Im using to build my 427 sb had a few opinions on head choices. One of them being the afr 227. So thats what I bought. Using a dart shp, forged rotating assy, t&d 1.6 offset rockers, and the tko 600 is in the box waiting on my engine to be finished up. I have a few other goodies in boxes to make it a sweet looking engine as well.

 

I would go with the AFR 220 competition ported heads. Stock valve spacing and flow comparable to almost anything anyone else makes regardless of port size.

 

I've got the new 427 short block sitting on the stand and I'm trying to figure out what cylinder heads I'm going to install on it. The AFR 220 is one of the heads to make the short list. This head has a .25" raised exhaust port and I'm trying to decide if that's going to be a problem. Does anyone have the AFR 220 heads with Hooker Super Comp headers? And does everything clear with these heads and headers?

 

1/4" raised moves the port up 1/8" and out 1/8" since the head is sitting at a 45 degree angle. Will effect nothing. The 220 competition ported are expensive but anything else you buy will need shaft rocker. Add up shaft rockers and other manufacturers heads the competition ported heads are reasonable. Easier to match intake and better port velocity for throttle response and bottom end. If your not running over 6500 rpm they will be fine.