mattbhm

Hey everyone! It's been a while since I've been here, life got in the way.

I am building an 85 Trans Am, it's going to be a pretty in depth build but still sticking to a modest budget overall.

More importantly, for the engine I already purchased an L83 from an 84' Corvette. Right now it's stock as I bought it(which may not be stock, I thought they had CFI). That is a basic standard intake, quadrajet, and awful smog heads. It does have forged flat top pistons.

My aim is for 350-400ft/lbs, but I of course will be happy with less. I just wanted to set a goal.

I am thinking new heads, intake, cam, and carb. Plus a custom dual exhaust. My issue is, what's the most cost effective way of going about this? I have the exhaust handled already. Mostly it comes down to the heads I think. eBay heads built with good hardware? Blueprint heads? Something else? Remember, I am on a budget here.

I'd really appreciate any input on the matter!

Vader

Personallly (if it were MY project) and short of installing an injection system, I would stick with and protect the QuadraJet like it was made of pure platinum. Regardless of what heads, cam, intake, and other trims you install, the 4MV/C is pretty tough to beat for driveability and raw flow. Others have varying opinions, I'm sure, but I'm usually left waiting for them at either the finish line or service bay.

skinny z

How have you verified this? Heads off?
The piston shape and it's distance below the deck will in part determine your cylinder head selection and head gasket.
Then comes the cam.
The least expensive way to 400 lb-ft is the good old Vortec head. In unmodified form they'll handle .450" lift with their stock springs and pressed in studs. I've done it with a Comp 268H equivalent cam.
Intake is dedicated and can be more expensive new but there are used ones to be had I'm sure.
Keep the Q-Jet but it can affect the manifold choice.
I suspect that it's not a roller cam block. The change over was in '87 I believe. While flat tappets can be perfectly fine day in and day out, they can also be problematic. Unfortunately, when you say budget, that often excludes a roller conversion.

GeneralDisorder

iTrader: (1)

I would sell that "corvette" engine to some other sucker. That 84 Vette motor will be flat-tappet garbage.

Get an L31 from a 96 to 00 truck. Better heads (if you use them - they WILL do what you are asking for), and stock with a roller cam. And they are cheap. Got mine for $200 fully dressed. Wasn't a thing wrong with it inside - just milkshake from a bad intake gasket.

GD

mattbhm

Yeah, I'd rather not go injection for a few reasons, but I am up for keeping the quadrajet. Thanks for the info!

Heads off, flat top confirmed. I cannot comment on distance below the deck, but I am happy to check if that's something that can be done.

I was considering the Vortec but I wasn't finding any good ones under $900/set. At that price, the Blueprint heads are at the same price so I wasn't sure. The other issue is I measured and I couldn't figure a way to use a Vortec compatible intake and have it fit under the hood.

It is not a roller cam block. I am considering a conversion, especially if I keep the carb. I'm not super worried about a flat tappet because it is more of a weekend warrior car and I don't honestly want insane numbers from it or anything. However, all I see is praise for hydraulic roller conversions.

Thanks for the info!

I'd rather not. Not worth the time to pull it out of my garage, get it sold, find another low mileage engine and get it back down in my garage. I'll either do a conversion or I won't. I do appreciate the comment, but I will stick with what I have for now.

NoEmissions84TA

iTrader: (1)

I'd rather not. Not worth the time to pull it out of my garage, get it sold, find another low mileage engine and get it back down in my garage. I'll either do a conversion or I won't. I do appreciate the comment, but I will stick with what I have for now.

Mistake #1 before you even get started.

mattbhm

I'm truly confused. On one hand, I see people saying a complete roller conversion is around $500(Correct me if I am wrong, I definitely could be). But then it seems everyone is recommending I sell this low mileage engine and completely start over with one that has rollers already. That is absolutely not worth it to me. Not just is this engine in a bunch of parts on my garage floor, it's also a 90k mile engine and I don't want to waste hours trying to get it sold and find another one.

So do the conversion kits not work? I stick with FT. Do they work? Then maybe I'll convert to a hydraulic roller setup.

Maybe I should have described my situation a bit better, I'll say that.

8t2 z-chev

no worries-just stick in the engine you have on hand and run it,flat tappet cam and all I have had the same engine in my car since 1993 and it has been very good-L83 is a very tough shortblock(you will need to swap the pan and pickup to standard if the 'vette pan is still in place-you will notice a windage tray to will have to tweak the standard pan a bit to fit) Roller cam is better technology,but flat tappet will get the job done-just use quality parts and take a few basic precautions if you have trouble down the road changing the cam is easy. For upgrade heads,consider Dart iron Eagle heads -stay away from the china junk! You are dealing with a 35+ year old classic car-like a '57 chevy was in 1992...

skinny z

That's where the problem lies. Quality parts.
I hang around on Speed Talk and the conversation revolving around flat tappet lifters and cam cores is never ending and always seems to be evolving. One day this manufacturer has the lifter of the day, then the following week someone is posting that that manufacturer's quality control has gone down the crapper. That said, it is possible to find the parts, but it takes some work and the end result is still a crap shoot because of the oil situation. And that story goes on and on too. This works. That doesn't etc.
What worked for one build yesterday may not work with the same parts today. That's what to take away from the above.
Jus saying.

To the OP, yes the conversion kits work. Lifters, properly sized pushrods and a cam button are what's needed.
If you decide to stick with a flat tappet arrangement, check on the latest offerings and see who has the best reliably from a street durability perspective.
(I mentioned Speed Talk and it's worth a visit there for some deeper tech).

skinny z

Having that distance is critical going forward. One couldn't say if that block has been decked or if the piston compression height is something other than the usual. Confirming TDC and then using a straight edge and feeler gauges will get a value that'll be close enough to work with.

Regarding the heads, what's your budget?
As for an intake, I believe any of the low-rise dual plane intakes, like a Performer, will fit under the stock Firebird hood.

I'll relate a story about flat tappet cams. It's when I got back into the game building a hot rod for the 1st time in 25 years (around 2005).
Bone stock zero mileage 350 shortblock from 1979 (that had been in storage since new). Factory flat tappets with an aftermarket cam and out of the box Vortec heads. Headers. RPM Air Gap. 600 Holley. Nice little package that while not blindingly quick, served as a summer daily driver and long distance cruiser for years.
Then it ate the cam.
Poor oil quality? Lack of regular maintenance? Can't say. But it cost me a full rebuild as there was nothing salvageable that didn't require machining or replacement other than the heads.
Next move was a roller conversion.
If the short block is of known good condition, then go with it. That's the cheapest route. You may find yourself yarding it out later but to get started...I don't see why not.


Yes, the roller conversions work.
Not only do they work but the cam profiles are such that there can be a performance advantage when compared to the FT given the constraints of the street orientated build.

GeneralDisorder

iTrader: (1)

You don't need a "low mileage" L31. You just need one in general. If it's running or was running it will likely be just fine inside. Mine had 177k on it and it was perfectly fine inside.

You will spend more on a conversion than just getting an L31. Mine was $200.

In either case you will need machine work. The main line on the SBC is bored but not honed to size, and older engines from that era can suffer from a variety of unfortunate machine issues related to the clapped out machine tooling GM was using at the time. Lifter bores that aren't drilled straight, starter holes that aren't in the correct location, decks that aren't parallel to the crank, etc.

No matter what block you go with you are going to AT LEAST want to line hone the mains so you can use a single set of bearings, parallel deck the block so it will have every piston evenly in the holes and will hold an MLS gasket with a nice new deck surface. And DONT TOUCH THE CYLINDER WALLS!!!! So you can forget about doing a rebuild without moving that hunk of iron out of your garage and back in. Not and do a quality job anyway.

If you want to be like every back yard hack that just throws bearings and a dingle ball hone through their farm truck engine and thinks they have a "hot rod" then by all means. But if you are looking for our advice then I strongly suggest you take it. It's free and most of us have been there.

GD

ironwill

How many times do you plan on rebuilding this engine? Do you expect it to last longer than it's initial break-in?

Based on quality-control issues regarding flat-tappet lifters and confusion over engine oil recommendations these days, you'd do well to avoid the problem altogether. Resign yourself to the fact that engine-building isn't an inexpensive endeavor---at least if you expect the result to last more than a few thousand miles if that long---and save up enough $$$ to do it right the first time, with a roller valve train. IMO, it makes zero sense to do otherwise, but it's your car, your $$$.

Fast355

iTrader: (2)

I have had more issues with factory roller cam based lifters than I have had with flat tappet cams. The lifters in my Hecho en Mexico L31 started locking up and eating the cam in less than 50K. The GM supplier for roller lifters like the LS7 lifters is flat terrible and has been for a while.

The last cheap L30 build I did had a Lunati flat tappet cam and Rhoads lifters with oiling grooves. Has about 75K on it now. When I pulled it out of my Tahoe I sold it cheap to a friend that needed an engine for his 99 Yukon Denali. He has been running it close to a year and still running well. Has run its entire life on Shell Rotella 15w40.

I swapped the factory roller cam out of a L31 in a fairly low hour generator a year or so ago. Cam was chewed up and the lifter roller wheels siezing up. Put a flat tappet "274" cam into it with standard hard faced lifters. Running it on Shell Rotella as well since the cam change. Running the roller lifters continuosly under 2,000 rpm prevents them from oiling properly. If the car idles alot and sees alot of low speed driving in bumper to bumper traffic the factory roller lifter wheels will fail from lack of lubrication.
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mattbhm

For some reason I stopped getting notifications from here. Sorry about that!

I think I will go with a roller setup, but I do think I'll keep this block. I found some Lunati kits with the retrofit lifters and a cam for around the $700 mark which doesn't sound that bad. Of course I am not picking anything until I have everything planned out, just getting an idea. I am on a budget, but it doesn't mean I don't want it done right the first time. I appreciate all of the info getting dumped into this thread and I am always happy for more.

As for the carb, I seem to have given away my good quadrajet. I don't know why, but I am 99% sure I did. I still have one, it's an all manual one that I think I dated to 1977. It's also missing the choke. Not sure if it would be worth a rebuild or just a replacement.

Thanks again guys!

skinny z

Seems to be some discussion around the short block. If it's a total unknown, as in mileage, maintenance and overall condition like what a compression test might have yielded, then it's best to take it apart and do whatever needs to be done. If it was sound to begin with, as in a known runner with no obvious issues, then leave it and build onto it. That's the least expensive route for now. It may mean that you have to address the short block at a later date. But I'll venture a guess that every contributor here has pulled an engine to do just that.
Go roller for peace of mind.
Just about any carb will do. It has to be sized suitably and obviously be in good (and complete) condition. I'm partial to Holley's or similar. Plenty of guidance here regarding tuning.

mattbhm

I read back through the messages that I exchanged with the seller of the engine two years ago. He said it had 90k miles stock and when he got it he brought it to a machine shop and got the cylinders honed and the bottom end examined. Whether or not that's true or a bad thing(depending on the shop) is another story.

With that said, I do think I'll go the route of building onto it and repairing issues as they arise rather than going through and rebuilding the bottom end now.

I still have to pick heads(leaning towards blueprint) and an intake, along with what roller conversion kit exactly.

Thanks for all the help here guys, I'll keep you all updated on how it goes.

Also, would 200cc heads be a no-go? I remember being told I should go for 180-195cc for a street car. These look very nice for the money but only available in 200cc. https://www.ebay.com/itm/SBC-CHEVY-3...QAAOSwZQxW2LMx

GeneralDisorder

iTrader: (1)

200cc is too large unless you are running a BIG cam on a 350. It simply won't use it. Really anything in the 195+ category wants more displacement and more camshaft. In a 350 it would be needlessly large for the street because a cam large enough to take advantage of it is not going to be all that street friendly. As port volume goes up, you shift the power and the torque higher. A 180cc head would be plenty for a street 350 with your power goals and a nice streetable camshaft.

GD

skinny z

There's your answer.

Don't be taken in by the E-Bay bang for the buck. There are plenty of examples where those heads need some work to make them right. There goes the bang for the buck part.
Personally I'd stick with a known commodity. Edelbrock for example. Brodix. AFR.
Aluminium is the go to generally but there are discounts for buying iron even with the weight penalty (and that's really all there is all else being equal). All those circle track guys can't be wrong.

Fast355

iTrader: (2)

Do not agree with that statement. Even with testing done with the Dart Iron Eagle heads years ago. They tested a 180, 200, 215 and 230cc runner on a 350. With a fairly mild cam the 215s only gave up 5 ft/lbs at the lowest rpm they could load the dyno and saw signifigant average power gains. I towed a travel trailer all over the place with 205cc aluminum heads with a 218/228 @ 0.050 on a 110 LSA cam giving .578 lift with 1.7 rockers. Had alot more torque than factory Vortec heads and the same size cam with 1.6 rockers. Both setups had Rhoads V-Max lifters adjusted per their instruction to give the most reduction in duration and lift at lower rpm. Now I run a ported pair of the same castings along with the same cam, same lifters and same rockers on an 11:1 383. IMO 200-210cc is a perfect runner size for a healthy running 350.

F-BIRD'88

If you want to kniw all about those specific NKB sbc 200cc port 64cc heads yiu can visit that popular sellers Website and contact them directly too.
There are various assembled packages availble.
Lots of tech info too.. like getting correct head bolts and washers etc..

These are good off shore castings and the 200cc size port works very well on hi perf 350's.
250 cfm as cast.
Same casting as Proheader, Assault, and AFR Enforcer as cast budget head. (Afr does there own guides etc (8mm)) Lots in field under this and other brands.. little no reported problems.
Do not compare with ProComp heads...

Every head you buy anywhere will need full cleaning and inspection.. eg valveguide clearance .

89fast5oh

I have a set of AFR 195 Enforcer as cast heads sitting in my front room right now. For around the price of ebay heads I would choose the AFR or Brodix ix180 or ix200 heads.

But I can see why the AFR as cast cost half of what my CNC AFR heads cost.

The AFR look like the Skipwhite heads, who knows they might just be cast in the same mold. AFR does the assembly and put their logo on the end. But for only $150 more I would go right to the AFR.

F-BIRD'88

These heads respond to hand porting very well also
for those that want to venture beyond the 250+/- cfm as cast ports deliver.

NoEmissions84TA

iTrader: (1)

Don't buy Skip White ANYTHING!

mattbhm

I think I am going with AFR 195 Enforcer* heads. $150-200 more than NKB but it sounds like the parts they use are substantially better. Plus a better company to deal with and probably better QC before being shipped.

GeneralDisorder

iTrader: (1)

My CNC AFR 195's are really nicely done. No complaints about AFR's quality.

GD

skinny z

I'd say with those heads you've got your target covered. Those are an easy 550+ HP capable part. And more depending on what you want to do.
Now your next decision is where do you draw the line. That would be compression, cam and purpose.
Now, to keep from getting burned here, I'm not discussing your chassis and your intentions with the vehicle. I'm only talking about the engine. The rest will be for you to determine. It really gets in the way when folks, with the best of intentions, say this or that because of that and this. It's up to you to build the lump to your spec and the rest of the car can follow. Of course it regularly gets done the other way around such as when you submit a cam recommendation form.
FWIW, when I spec an engine, I set a target. Eg. The most torque. Or the rev range. Or I'm pulling a trailer with my SUV. Whatever. If you want a cruiser with a broad RPM range, then work towards that. If you're after a solid drag racing engine with the rest of the supporting parts as part of the plan, then go that way.
Not that it matters, but what I have in the works now is all about the maximum lbs-ft I can make. That really levels the playing field when it comes to the cam spec. I've sent off several cam requests to the usual suspects and they interpret my intentions and it's plainly seen in the cam recommended. When I hit them up a 2nd time, with my spec refined, the recommendation comes back somewhat tweaked.
Hope this is food for thought.

mattbhm

Thanks for the informative post!

I am building up the engine before moving onto the rest only because the engine is sitting unassembled(but oiled up) in my garage. I absolutely plan on building the chassis and the rest of the car to handle whatever I put in the engine. Safety is of the utmost importance. Right now I only have SFCs for the chassis but it's a start.

As for the engine, I am hoping for a fun weekend car that could handle daily driving if it comes down to it(for a short period of time). So I guess it's like I want the most ft/lbs possible without giving up drive-ability. No track of any kind, no speed records, just fun off the line.

skinny z

Well, you'll certainly leave a lot of performance potential on the table given what the AFR 195's are capable of. While they flow a ton and can take care of a 350 in the high RPM ranges or satisfy bigger cubes it was pointed out to me (in another forum courtesy of Vizard) that they also have very good low lift flow. The 2.05" intake valve doesn't hurt here. And if it's torque you're after at the lower end of the register as it might be for a street car, the AFR's are more than capable. It'll be the cam and induction that determine how many lbs-ft you'll make and where.
It seems to me you'd have liked the results of the 86 IROC I put together a few years back. Now while it didn't have a 195 cc cylinder head, the 170 heads combined with a shorter cam (224@.050") AND a converter made for a spirited ride that could be (and was) driven every day. It could get out of its own way on the street too. At the time, the OEMs still hadn't released the monsters they have today so it was competitive.
By way of example, a dual plane intake, a suitably sized carb for the RPM you want to reach and a decent (but top end limited) exhaust were the ingredients that produced that ride.
By the way, SFCs were the only real chassis modification aside from an aftermarket torque arm and panhard bar (both adjustable) on that car. Drag racing necessitated lower control arm relocation brackets as the car was lowered and messed up the rear geometry. I needed the added bite from better rear end angles to go along with the slicks.
Don't forget your gearing either. It's often been mentioned here that with a given power output, gearing and converter (or a stick) will offer the greatest transformation will respect to cars overall feel.

NoEmissions84TA

iTrader: (1)

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