I am trying to decide between upgrade paths. I want an estimate of how fast this combo could go:

stock bottom lt1, most/all boltons (headers, exhaust, elec wp, cai, gears, etc) plus ported afr 227's and a good cam (gm847 or better) NA, 6spd, dot 275s, full weight, 94 pump gas

Could this go high 10s or w/o exotic head work? I don't want to go FI unless I really need to. I'd build the bottom to 383/396 later. What I want is an easy low 11 NA street car and need to know if this will do it so I can get heads for higher compression and if it won't ones with more CC so I can SC it.

I realize there are a lot of these types of questions so I thank in advance anyone who could help.

 

AFR 227 on a stock bottmend would be a complete waste. To be able to use such a big port effectively you would have to spin the motor FAR beyond the reasonable range of a stock short block... not to mention far beyond what the factory computer can handle.
If you intend to increase cubes later, but still want good performance now I'd suggest a set of GM LT4 castings.
Steve...

 

He couldn't have said it any better.

Consider some heavily ported LT4s or ported AFR 195s if you're going to stay with the stock displacement. The more volume in a runner, the faster you're going to need to spin the lower end to get the velocity you need to make power. 227s would be a paper weight on top of a stock block.

 

The 227s would just be the first step. Like I said I'd increase displacement later. I'd also use nitrious at the track likely. I don't want to go with GM LT4 heads as they are little improvement over the LT1s. If I go NA I want to use the best heads possible with my final build in mind. I fully realize AFR 227s on a 350 is not using the heads to thier potential. I am wondering how fast this combo could be before I do the bottom end?

 

To get any power out of that combo, you'd need to spin the motor well over 7k, beyond the limits of the stock rotating assembly. To answer your question, not very.

And who said LT4 heads are little improvement over stock LT1 castings? LT4 heads flow over 40cfm more than a stock LT1 head, which is extremely significant.

You do also understand that a 227cc runner is suitable for 400+ cubic inch engines designed to spin to 7k plus, right? It seems like all you'd like to do is spend money. If you say you're going to do the bottom end later, why not wait and do it all in one step?

I would go with either a fully ported Lingenfelter or GM LT4 head or an AI/LE full port package. 227s are a waste for your application.

 

The 227 is a great 6500-7000rpm stroker motor head. If that's where you want to go, then go ahead and get the heads. With a moderate camshaft and enough compression (good dynamic) the AFRs will provide good performance on a 350.

I'd go ahead and build the engine around these heads rather than spend money modifying stock heads... then chunking them later. All depends on your goal for the stroker build. The 227 is definitely a head that you can "grow" with.

-Mindgame

 

Mindgame, you're speaking my language. I've seen ppl run these on sub 400ci motors. What I am thinking of doing is building around these heads. I don't want to buy LT4's and ditch them. When you say "AFRs will provide good performance on a 350." I'm sure they will but my real question is how good? Low 11s is my guess and mid to high 10s with a 383+. Am I in the right ballpark or out to lunch?

 

Kick your compression up as high as 11.5x1 static and go racing.
Remember the larger the head the smaller the cam and that makes for better driveability.You also need an intake to compliment the heads.Don't forget the TB and CAI and filter.

 

I had originally planned on runnng the 220s on stock bottom end, but the thought of losing a piston into the heads really worried be, so i went ahead abd had a block built.

Anyways, i agree that you can make some nice power with them, but if you arent aware, you will need lots of special parts to make the 227s work (offset valvetrain, regaurdless of what AFRs website says)

 

atljar,
The 227's take regular valve train with no offset.The RR's set angled to the head,like TFS on a Ford because of valve location.You have to have AFR pushrod guide's.

 

If he did this: big heads small cam; where would he be makeing power at? What would his dyno graph look like? I'm guessing he wouldn't have a flat torque curve?
-b

 

Depends on the cam.

 

Larry is right, the AFR227 will work with standard parts. Use the AFR guideplates or Isky adjustables to get everything lined up. You'll also need an AFR stud girdle cause the rocker spacing is a tad different from some other heads. The geo, may look a little strange in comparison to what you're use to seeing but it works just fine.

You should see some of the old castings that with relocated valve centers using stud mounts and adjustable guideplates.

-Mindgame

 

Johnny o,

Don't get too hung up on power numbers. You can run low 11's with just 400-425hp at the rear wheels. The engine is just one element of a good track setup. I don't doubt that you could do that and better with the 227 atop a 350. The best thing about it is... it won't be holding you back when you decide to build the stroker.

-Mindgame

 

Thanks for all the help Mindgame.