I’m fixing to install a 434 with a new 5-speed transmission in 1972 and have a question or two for you scholarly folks - for induction ~~~~ It’s on its way and I’m pretty pumped.. Many have raved over the Edelbrock Pro-Flow and others think the Fitec does a better job when it comes to intake – what do you think? My hp is the 625-650 on motor – I’m building a NOS motor so it will go another 200 + hp easily on the juice. Soooo – what should I consider for induction to keep everything lively and to wet the seat of her britches when I want to amuse her? You don’t have to like my statement – I don’t really care – but what I do desire is your clear decisions-!! make a good combination for the little 72? When it comes to intake? Please help me understand your answers by explaining your thinking? Currently, I/m using Brodex Dragon Slayer heads and intake but don’t have an induction plan. I need all the help you can offer. Thanks!!

 

I would chose the one that can be tuned for NOS. From what I understand, the Edelbrock Proflo 4 unit is easy to upgrade HP wise by just increasing injector size. I would think if you’re building a 800+hp NOS engine you may want to look at Holley’s HP EFI for even more tuning capability. It’s expensive, but so is a new replacement engine. I’m assuming you’re wanting to go multi-port sequential injection? Do you want the traditional carb look or more modern EFI intake? Of corse hood clearance will also play a factor. And the intakes flow capability... Your tuning capability... What’s the point of buying a fancy EFI system if you have to take the car to a shop every time to tune it... $$$$. Lots of decisions, but it up to your preference.

 

I'm a Holley HP fan. I've been running their Dominator system on my car for many years and it's great. The HP will likely do most things you want...but the Dominator adds more features.

JIM

 

434 implies.030" over. What are you using for a block? If you're planning that kind of horsepower I would recommend something better than a factory casting.

 

Ditto......

 

A better question would be to ask about the build specs?

 

Good point, but when he says 434 that tells me he's working with a block that's .030" over, which also suggests he may be building this thing on a used block. No one's going to bore a brand new block for a measly 7 cubic inches. It's possible that he has found a used Dart block, but if he's trying to make 800 horsepower with a factory 400 block, it probably doesn't matter what the rest of the build specs are.

 

I always recommend going with 434 instead of 427 when you buy a dart little m or Motown block. It used to be only $100 more when you buy the block or short blocks. It's the cheapest additional hp that you can buy. I have my 434 block being decked right now because of the 3rd rebuild

4 inch stroke SBC's have problems with cylinder filling

 

Interesting. I had not thought of it in terms of cylinder filling. A .030" overbore would unshroud the valves by .015" which would help to mitigate the disadvantage of the smaller bore of a small block. Has anyone ever done back-to-back dyno tests to see how much of an advantage the 434 offers over the 427?
Even so, if I had it to do over again, I don't think I would go with the 434. There's just something I like about being able to say I have a 427

 

m

454 BBC has a 4 inch stroke and the most powerful BBC engines had big rectangular port heads with big valves. Like 280 cc with 2.19/1.88 valves. The small block has tiny in comparison. So to make 650 hp 427 SBC you need the biggest flowing heads with 2.10 or bigger intake valves. AFR 235 and 245 cc are about the best for the street catagory. A bunch of us here on the forum use 227cc with the comp porting.

one forum member has a 4.155 X 3.875 427 that is a real runner.

 

4.155 x 3.875 works out to 420 cu ins. Not that that's important. I have the 'conventional' 4.125" x 4" 427 with 220 AFR heads and 2.10/1.60 valves and 'a real runner' describes it well. They are pricey but hey, horsepower costs money. I can't imagine building a 350 or 383 again, knowing what a 427 small block can do.
It sure is easy to get spoiled. Many years ago I had a 283 in a '71 Vega panel and I thought it was fast.

 

One of my employees is building a Dart Block 427 SBC with 350 mains and he’s using Brodix 18 degree heads with 2.14 Intake and 1.60 exhaust for a 1970 Nova street car , should be a runner when he gets it done , those heads are beautiful and can be purchased with 38cc combustion chamber though he opted for 68cc chamber for the 427 since it’s a street motor

 

Typographical error he called the 3.875 a 421

My first 427 had the light weight 350 mains 4340 crankshaft and broke. I went to the all out 400 main light weight callies pendulum cut 42 pound.

In retrospect I should have bought the 4.125 stroke crankshaft for 447 ci. They were the same price.

The weak link is everything behind the engine with our IRS

 

The 434 build it my 69 is has a real whimpy build compared to most builds with only PRO1 195 at 64 cc. I'm suspecting only 425 to 450 hp, but it doesn't matter how they are setup they sure are torque monsters. T

 

It's a Dart Block (new).

 

A lot of machine shops will punch a brand new Dart block just to ensure it is straight......4.155 finished bore. The block will go 4.185 no problem...some catalogs have shelf 4.165 pistons. Not really a big deal just one extra process. Sometimes in a jam.....Dart will sell you a 4.030 block when the larger ones are backordered so you do not have to wait, for a discount......most bore/hone them right to 4.155.

Jebby

 

Yes sir, and there-in lies the million-dollar questions? Who are you folks getting the heavy-duty pieces from? I'm really looking forward to this build and you guys have stirred the pot with heavy cream...I hope that didn't sound too gross....I meant it harmlessly. My builder is using a K1 forged crank and forged H beam rods with Extreme duty fasteners. The cylinder heads are holding up the build - just waiting on Brodix with a whole list of other folks.......... I'm still undecided about choosing the intake and induction. The response to this post has been wonderful but I'm still not quite sure what route to take. All and any suggestions are welcome. The information you folks share is amazing and very much appreciated.

 

Think if i were to build 427/434 with 23 degree stuff it would have at least afrs 245 head on it or larger then that. The oil pan would be huge as i could get away with. Right now im souping up a bad *** 235 inline 6 with new fenton duel exhaust manifolds. 😂

 

Lot of cubes and agree on the 245’s with 23 degrees , it’d probably take a custom built intake to use 18 degree style heads in a C3 or a fairly tall scoop or L88 hood at the minimum

 

I built a dart little M based 427 about 12-13 years ago for my 76. It went into storage for 11 years and I am working to get it running again. I used a custom, Dr J ported Motown intake with the Fast xfi multi port system to fit it under the stock hood. I had to mill 5/8” off the top and use a drop base air cleaner. I previously had an edelbrock proflo 1 intake ont which fit under the good with a drop base air cleaner. AFR 210 heads. Msd Crank sensor. Pump gas motor.

mistakes I made.
1. Solid roller cam was too much with 1.6 rockers. 630 lift, and 248 duration at .5 as I recall. Probably fine with 1.5 rockers.
2. Should have gone with the Tand D shaft rockers that the engine builder recommended instead of the comp roller steel rockers and stud girdles. More money though.
3. 210 Heads weren’t big enough. Should have got the 227s. 245s look even better and I may eventually upgrade to them.
4. Should have rewired the car. I’m doing that now with an AAW kit. The efi system was getting signal interference issues in speed density. It ran great up to 5800 rpm then flattened off I think due to a lack of airflow. I was running it in alpha N mode.
5. Hooker side pipes had spiral baffles which were restrictive until uncapped.
6. Stock hood and milled intake and drop base air cleaner were all restrictions but kept it looking stock ( except for the 4-link 9” diff)
7. Clutch slippage issues with the center force dual friction clutch. I bought a McLeod dual disc and hydraulic bearing setup to address this.

I’ll probably add nitrous eventually to avoid an immediate head upgrade. I got 410 rwhp at 5800 rpm which was ok but underperformed I think due to the airflow, clutch and signal issues noted above.