Hi
I recently pulled a 350 from a 77 Caprice Station Wagon at my grandfather’s farm. The car has been sitting since the mid 80s but according to my father and uncles the engine ran and drove fine when it was sat. The reason my family sat a perfectly running car was because the car was given to them by a wealthy women up the road who was sick of the other problems with the car. The car had broken door handles and the interior was garbage. After further asking, I found out that the car had a relatively new engine in it because the old one was blown and she had a new one put in. the block is blue which could mean nothing but a pretty good mechanic told me that these blocks were good and generally were not put in by gm (he could be wrong so don’t take my word for it). After pulling the engine I turned the crank with a tire arm and a pipe for leverage to check for compression, it had compression.

I plan on rebuilding this engine for performance, so I’m not going to just throw in some new oil and springs and run it. I plan on pretty much buying everything new that I can (maybe not the heads $$$$). Currently I have taken everything off down to the heads and block.
Originally I wanted to stroke it to a 383 but I took off the oil pan and it’s only a 2 bolt. Now I know many people have different opinions about stroking a 2 bolt but I don’t want my post to turn into a 2 bolts aren’t strong enough argument. I look at it like this, I can still build a pretty decent 350 and since I’m only a college student and can’t afford to put money into an engine that might blow in a year or two. I plan on dropping this engine in my 92 firebird which is going to be a street/strip car, mostly street for I might just take it to the track for qaurter mile times. I want to build this engine best for stoplight to stoplight street racing (low to mid power) and would be willing to compromise power for high speed racing. I look at it this way: an unsafe start ticket is nothing to worry about compared to a 150 in a 65 ticket.

Now that I got the background and planning info out of the way here’s where I could use some tips. I know from researching and reading some info on engine rebuilding but I don’t have any 1st hand experience like many of you gear heads on this site have. I do have an uncle that is a very decent mechanic and has rebuilt engines many times but he lacks new technology info and the initiative to build a fast car. he’s kind of one of those old gurus that puts down everything saying things like "your car is fine the way it is" and complaining how much work everything is. But I bet if he looked back at when he was young he be doing the same thing as me. he admitted he’d help me rebuild the engine and use his garage but when it comes to taking the right path and choosing the right parts I would like better advise otherwise the engine would be a late 70s 350 with stock parts.

My first question is about magnafluxing. Since the engine reportedly ran and had compression should I spend the money to magnaflux the block?

Now I know there may be cylinder ware and a machinist may recommend boring to a certain point, but say the cylinders are pretty good. What should I have the engine bored to? I was thinking 30 over but maybe I could go 40. Someone told me never to go like 50 or more over unless you plan blowing your motor in a year but I think he was only talking about off-road drag cars. Remember it’s a 2 bolt.

Since it’s a 2 bolt. Maybe I can strengthen up the main by having splayed caps installed. Does anyone know if machine shops do this? Price? Would it be worth it?

Now I know prices can be cheaper and more comfortable knowing parts will fit by buying a rebuild kit but if I can spend a little more money to get the best performance possible by buying parts separately than I will. Now money is a problem but I’m a very good saver and would rather get the best performance I can while I have the engine on a stand and not in the car. I don’t want to think back in a couple years saying I wish I went with these pistons or cam...ECT. Can anyone recommend any rebuild kits; I don’t care about emission testing since in NY, inspections are easy and I have many friends, so if the kit is meant for strip only and puts out more power so be it(its not like California here). Also if anyone has gone thru this b4 and recommends buying parts separately then let me know.

Not sure what I should do with the heads. I know I can port and polish them but it would be a little tougher since they’re iron heads or I could spend a grand for good heads. What do u guys recommend and how much more power can I get by buying new heads rather than to port and polishing them.

Next thing is cam. Many builders recommend choosing your bottom end parts and heads first. Which sounds like a good idea. But after looking around at cams I became confused about their specs. I’m not sure which cams are better for low to mid power because of their specs say for instance a cam offers 1200 - 4200 rpms 260 duration .427 lift and 110 lobe separation. Now correct me if I’m wrong but the confusing part is that when you’re at a stand still and you accelerate your not shifting till the power band so you need your power at higher rpms. I know I may sound stupid but I’ve been trying to understand cams for awhile and I’m still a bit confused. I slightly understand the other specs but I’m still not sure what the better range of numbers is for duration, lift and lobe separation to get the best low to mid end power. So if someone could give me number ranges for these specs to get the best low to mid power that would be great.

Now I could be wrong but I think intake and carb are pretty easy. Just choose the intake and carb that offer the best cfm air intake and consider clearance.

I’m sure somebody out there has put and older style carbed 350 in a thirdgen firebird so can anybody offer advise on the oil pan and headers for clearance issues? I don’t think there’s any difference of third gens but mine is a 92 if there is.

I know I’m going to have to get new motor mounts but that’s pretty simple.

It’s kind of early to think about transmission and rear-end but many say it’s good to have your drive train planned out in order to get the best of what u want from your car. In my situation I want a car that can get from 0-60 fast. My firebird is an automatic but as we all know there is already a hole above the tranny because the auto shifter is on the floor. Is the hole in the right location and big enough to put a manual tranny in? Many have told me it’s a pain to put a clutch and tranny lines in but would it be worth it?

I know the higher the gear ratio the faster off the line the car will be but I don’t want to be only able to go 60mph and I don’t want the wheels to spin only at the touch of the gas for that would cause me to loose races.

For the power the motor will have a stock tranny and rear-end would obviously be a bad idea. So can anyone let me know if it’s worth it to rebuild a tranny and rear-end with stronger aftermarket parts or buy an aftermarket tranny and rear-end? What are the better quality aftermarket transmissions and rear ends out there?

I m sorry about the extremely long thread but I tried to explain everything so the people who may try to help me can actually offer answers instead of more questions because the author of the thread wasn’t specific enough.

Thanks,
Tim  

I'm absolutely amazed that 2-bolt blocks scare people away from something as simple as adding a little bit of stroke. Please realize that without significantly changing the valvetrain and induction from slightly warmed-over stock, increasing the displacement will actually hurt, in a sense of the word, efficiency. Specific output will decrease. Let's assume that you're building a fairly mild street machine that can make 1 hp per cubic inch (pretty darn easy for a modernized 350) now you leave the induction the same, the valvetrain the same and increase the stroke. I'll assume that there is a slight increase in compression, but that's it. This helps soften the "hit" in efficiency but let's say your specific output decreases 5-6%. Your new power is probably 355-360 horsepower, wow that's about 10-12 higher than the 350! That's all! Do you really think that will max-out a 2-bolt block? Especially to the point of breakage or cap walk! The real differences come with stroker motors with larger induction systems and cam profiles where the larger engine can start making the same, and depending on the performance "ability" of the previous engine, more specific output.

Of course you want to spend the money to magnaflux the block and heads. There has been many (I've seen several myself) running engines that had cracked heads and or blocks. You really don't know the history of this engine and especially since it's been out in the weather for 25+ years to have no idea what shifted, expanded, etc. You will be increasing the temperature within these parts and the stress on these parts so starting with a crack is usually a good way to get water in the cylinders or oil over time. I thought magnafluxing was standard procedure and included with the prices of many jobs. I can't imagine a machine shop wanting to do work on a block that would be destined to fail, if your machine shop thought this could be skipped I suggest finding someone else.

I see that Eagle is now selling splayed 4-bolt billet caps for about a $100. I'd assume that having the machine shop install these would be anywhere from $150-$250, you'd better ask. Milodon also sells these three caps in a kit for about $270. The Milodon kit might reduce machining costs, especially if your block requires an align hone anyway. Here's a quote from them on the installation process... "Only .030" of material removal is required upon initial installation, which will allow 100% cleanup on a damaged block. The drill bushing used to drill and tap the side bolt holes is included in the kit. The side bolts can be installed by anyone with a hand drill and a tap. If the block has square main registers, the block needs only a standard align bore to finish the job. Milling the mains is only necessary if the main cap registers are not square."

Buying "kits" is usually the best way to save money. I'd recommend Northern Auto Parts for dirt-cheap rebuild kits with some fair parts in them (you have to "option" them in). If performance is of utmost importance (maybe trying to make 425+ horsepower) I'd say buy a imported rotating assembly (Eagle, Scat, etc).

Anyone who says "port and polish" usually doesn't know what they're doing or even what porting means. I suggest not to go screw up your heads without a lot of research and talking to someone who knows what they're doing. Stock pieces like what you have are good to start on but if it's something you won't ever do again I suggest buying a set of assembled heads. Shoot, the best option is probably buying a set of new heads no matter what with the cost of machine work that you will put into a set of 30 year old castings. With vortec heads you will probably see a 20-30 horsepower increase over the stock castings (depending on their condition, casting number, valve job, etc). Now with aftermarket aluminum heads and corresponding compression, camshaft, carburetion, and induction increase the gains are nearly endless. I wouldn't be surprised to find nearly 100 horsepower going this route but maybe 50-60 is more reasonable with a lot of street action involved. How wild you can go depends on the car's setup (converter, gearing, etc) and what you can stand on the street or really what your goals are. It requires a little education on the subject because it's nearly impossible for me to sit at this computer and tell you exactly you want in a performance engine...

An important aspect of camshafts while accelerating from a stand-still is the mid-range power coupled with the stall converter. The larger the duration the more power is shifted up the rpm curve. For example the cam you listed is very mild, near ly stock in size so this cam would probably make a peak torque at around 2800-3500 rpm in a slightly-warmed over 350 (maybe a little bigger carb and slight increase in compression). Now stock stall converters are usually rated at 1800 rpm, which is a very tight converter for highway driving, fuel mileage, etc. Now let's say this converter foot-brakes at 2000 rpm and "flashes" (actually starts the car in motion) at 3000 rpm, this is around or slightly below peak torque, this is good! The engine will launch at peak torque and be "picking itself up" to peak power where you can go onto the next gear. Now let's say you have a cam with 290°. In the same warmed-over 350 the peak torque would probably go up to 4000 rpm. Now this converter will flash significantly below peak torque and the engine will need to "pick itself up" which is difficult for the engine because the larger duration and increased overlap has reduced it's low-end output (it's harder for the engine to accelerate out of it's "power band")

I highly suggest picking up a few books and doing some research on what you think would be a good camshaft duration for you. Obviously there are outliers that can't be used (like 290° of seat duration with 8.5:1 compression and a stock converter) but there is a lot of choices within an acceptable range. Take a look at some built motors in magazines. There are tons of 350/383 builds online under the Primedia mags...

I can't inform you about fitment issues or putting a new rear-end under your car. As far as I'm concerned I've already written a short story...

All I can say is the gear ratio and converter depend on the power band of the engine. Higher numerical gears are required with larger cams, bigger carbs, larger induction areas, etc. How high is too high is figured out pretty easily. If you have a 28" tall tire, 1:1 final transmission ratio (as like a TH350/400) and 5.13:1 rear end gear ratio at 65 MPH your engine will be churning about 4000 rpm. In this case I hope your car never sees the highway for any extended period because that's workin'! Now put this gearing into a #3700 car with a 350 with a single plane intake, 850 carb, big roller cam with about 250-260° of duration at .050", 11:1 compression, maybe some 200cc heads, and you're into the low 11's in the quarter mile. This combo would also need a 4000+ stall converter. Now hopefully from my examples you can see the high and low end of the spectrum and figure out yourself where you want to be inbetween.  

sorry for the long delay had some troubles in college. i have reconsidered what i want to do with the 350 block. even though its a 2 bolt main i want to stroke it to a 383. i think it'l be okay bc im building it for a street car emphasizing low end torque. i know people may question why i want to sacrifice top end power for low end power this is because i want to be able to beet other cars on low traffic roads around me with 8th to 1/4 mile straight patches. so i guess what im tryin to say is i want to build my 383 to be the best at 8th to qaurter mile street racing.

Now i know b4 i said that im on a budget, but not to take your guys advice for granted but i want to do more than keep the stock bottom end and throw on top end stuff. i pretty much wanna make my own crate engine using the old block. now i know i could probably buy a crate engine for the same price but it wont match my specific specs for low end power i want. i want to be able to go to the gas station for fuel so i need it to run on pump gas.(around here they have 87, 91 and 93). from what iv heard u cannot go much over 10:1 compression on pump gas or you'll detonate.

Now i know to raise compression several methods can be done and i know to build a 383 u need to bore the cylinders 30 over. the other ways to build up compression that i know are to deck the block, small cc chamber in head and a thinner head gasket. i want to find the cheapest way to get around 10:1 compression unless i can go more on pump gas.

so ideally if i was a millionare which parts would i buy to build the fastest 383 for 8th to 1/4 mile street races. after getting this info i can understand the manufaturers specifications on the elite parts in which i can shop around and make compromises between performance, quality and prices.

from looking around iv found a kit that is probably ideal for my situation if u can suggest better go ahead

Northern Auto Parts :Chevy 383 Stroker Engine Kit - HP383KHW Hypereutectic Piston W/Crank

http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=1674  

Even though money helps, just throw a lot of money at an engine may not be the best coarse of action for performance (even "ideally"). What's important is that the engine operating range coincides with the car's gearing.

A maximum of 10:1 static compression with iron heads on 93 octane (depending on your camshaft and climate) is probably too general but a fair assumption. More than likely, aluminum heads will make this number more safe. If you are going to measure your compression ratio VERY CAREFULLY AND ACCURATELY then maybe 9.6-9.7:1 with iron heads is a better idea.

A cheap way to add compression is to do what you're already doing. Add displacement! I highly suggest learning your way around one of THESE static compression ratio calculators. You will soon find out what you need to get at your target compression ratio.

Just so you know, the rings and camshaft leave A LOT to be desired in the kit you listed. More than likely the rings are standard gap where performance engines really need file-fits and the camshaft is a cheap, ancient; slow Crane grind that will be slightly down on power compared to some other more modern grinds. I'm sure you know the limits of hypereutectic pistons as well and that the crankshaft is a cheap Chinese import but they probably will both support a good 400-450 horsepower. Please also realize that the head gaskets that come in that kit will be .040" thick Fel-Pro composition style gaskets. Steel shims are really becoming a thing of the past. I know Mr. Gasket and Doug Herbert still sells some dirt-cheap ones but really the growing trend in performance engines is having the stock blocks decked to zero piston-to-cylinder head clearance. This really should be done in almost all cases if possible.

Feel free to continue with your questions...