OK, after all of my thoughts, I want to put a 350/383 in my 91 V6 Firebird. So, I want to use this thread to answer some questions for me.

OK, I was looking through a Chevy High Performance magazine, and came to the double page ad that shows the performance catalog thats like 5 inches thick. Well, it shows like a SUPER MASTER REBUILD KIT with alot of stuff. It comes with like New Pistons, Rings, Cam, bearings, Rods, etc. Heres where my questions come in.

-Do I want forged? What is the power level when you want to go forged?

-When I look for a block, what year(s) should I look at?

-Do I want a 1 or 2 piece Rear main seal?

-Do I want 2 or 4 bolt main?

-Do I want I beam or H beam rods? Why?

-What length rods do I want? Why?

-How will I get my speedo/Tach/etc. to work? Can I just swap in any V8 cluster from a 91-92 bird?

-What are some good heads to get on a budget?

-What kinda gas mileage would I be looking at if I put say 400 HP to the ground with a carb?

Thanks for the help in advance. Sorry for asking so many questions

 

Im doing pretty much the exact same thing you are, with dropping in a v-8 in place of my 2.8. I HIGHLY recomend getting "How To Build Max Performance Chevy Small Blocks" by David Vizard. Read that and it will answer all or most of your questions, another good thing to do is search the forums for your answers.

Forged seems to depend on if your adding some kind of power adder, IE supercharger/turbo/nitrous, but depending on just how much boost or spray your adding dictates if you need to go forged, its always nice if you have the budget to do it, and then not have to worry about streigth as much down the road.

a 1 piece RMS has advantages of easy changing, and can seal better, but can go either way really. As for the 2-4 bolt mains, if you want to stay under 450-500crank HP the 2 bolts should hold, i highly recomend some ARP bolts or better yet studs for them. 2 bolts are also nice, just incase project creep sets in, and you want more power from a supercharger or something, you can splay the block and add even more holding force.

H Beam Rods are very strong, but unnessary if you are staying under 500HP, a good aftermarket I rod will hold pretty well to 400-450hp, you can reuse the stock rods after some reconditing, but the cost comes close to just getting new ones.

A longer rod helps with mechanical efficency, but if you are stroking the engine, then the 5.7" seems to be the best bet for cost/power wise, you can get 6" rods for a 383, but i feel the distance from wrist pin to ring clearance hurts the durabilty of the piston. If going a rebuilt 350 route then i highly recomend getting the 6" rod combo with matching pistions.

As far as the gauges go, im not possitive on the 90+ firebirds, but my 87 is electric all the way across, So sense you have to swap trannies to mate up the the v-8 if its an automatic, you can just reuse the speed sending unit on the new tail shaft. RPMs are pretty easy to solve, if your v-6 guages has the 8k RPM tach, then you can go the the junk yard and find another 3rd gen firebird/trans am that has a v-8 in it, look at the tach, some will still be 8k but alot will be 6k, pull the cluster out, remove the needle and take out the two little screws and you have your self a new inlay for a v-8 engine. All the other stuff with water, oil, voltage and gas will all work, when you remove the old oil and water temp sensors, you will see on the new v-8 that you can screw them in, just in different locations, for oil its at the back of the bock, along the ridge that the seal for the intake sits, water is in the side of the cylender head between cylinders 1 and 3. When you are in the cluster chaning the inlay, go ahead and pull the SES light, cus since your running a new carbed engine, the ECM will go nuts looking for sensors that arnt there anymore, but i do recomend a fuel pressure and A/F gauge to moniter the workings of the new engine, all other gauges will work regardless if it thinks the v-6 is in there or not, it just needs power.

Now for somethings you didnt ask, accessories ^_^, im using a Surp set up off of a v-8, the air conditioner will need new lines but will still work just move it over, Power Steering uses the same pump, but a larger pully, so pull off the pump pully from the parts car and use your pump if you know that its good. ALT will be backwards, meaning that one of the mounting tabs is treaded and the other is the passthough/larger flange set up, if that makes sense, well anyways on teh v-8s with the surp set up, its reversed, you can not really modify the ALT to work properly, but can rigg it to mount, you just have to get some new bolts and a drill bit, i would recomend a replacement for a v-8 car, or even the donar car.

How about cooling? If you havent read the FAQ guestions at the top of the swap forum, it list that if your radiater does not have the drivers side inlet from the thermostat, then you will need a replacement, there are some ways to go about this, junk yard agian, if you can find a good replacement, or buy a new one, but you can still use the stock cooling fans and assybly for it, make sure you have the air dam intake under the support for the rad. I would also and i am adding a good size oil cooler to help the bottem end, along with a tranny cooler.

Anyways, im building a 383 with modded Vortec heads (ported/polished, clearence for larger lift cams), and planning on making no less than 430HP at the crank, and possibly a little spray on top of that. Im thinking with this combo i could see up to 350 at the ground, but thats enough for some lower 13sec passes pretty easy, and still sound pretty mild, and a good daily driver.

Im using an 010 2 bolt main block, came in trucks/cars around early 70's SBCs came with 2 piece rear seals till 86
Used vortec 062 heads, $250-350 from ebay, then another $100 in tools to modify them for higher lift
Edelbrock Performer intake $100-145 used from ebay

Parts From Summit
Eagle 5140 383 crank $189
Eagle 5140 SIR 5.7" Rods $235
Sealed Power 383 9.73:1 Hyperutic pistions .030 w/ moly rings $239
Comp Cams K kit for 262 cam, $309
Remand Edelbrock 750 Performer carb with electic choke $295
New HEI Distributer

This gets me from what ive researched a 383 that can handle 500+ HP at the crank, and handle RPMs of 6k with out too much fuss

Not too sure on MPG 10-14 city, if i stay out of it hopefully

Like i said im doing the same kind of swap, using a performnce built 700R4, and im building the engine now, spreading it and money over the next few months, this is research that i have done, but seriously get the book, i got mine from Overstock.com for like $12.41 plus another $2.50 in shipping. The book helps alot with building the correct combo of parts to get good performance and relaiblitly.

 

WOW my first monster post, anyways one more consern, FUEL, if you use a mech. pump on the engine, then you will have to reroute your fuel lines. If outside electric then you can put inline with your fuel feed line, then in the bay just make a new line to run from the solid to the carb.

No matter what unless you use your EFI pump and a regulater with a return, you will have to drop the tank, and get rid of the stock fuel pump, and put in just a fuel pick up line, if you try and pull fuel through the pump then it will cause too much stress and you will not beable to feed the 400-500HP that your looking for, im using a Holly Blue with a regulater at the carb, and using the existing ruber fuel lines in the engine bay, with some extending for feed and return.

 

Wow! I havent been able to post in awhile, Ive been busy. But, WOW, youve answered all my questions. Thanks for the help, and the time it took to write all that.