a little backstory. My son, now 16 and I are working on my first car that has been garage kept since 1998 but has not been started, moved or touched since then. When we first started working on it last year, we put some Marvel Mystery Oil in the carb and bottom end, new battery and poured gas in the carb and it fired right up and idled, as long as I could keep fuel in the carb. It ran smooth with little to no smoke. The car is a 1987 base Firebird with the H engine code, 305 carbureted with a 700R4 trans. He has liked the car since he was about 9 or so, as he got a little older he asked if we could fix it up and it be his first car. Why not, right! Before I ask the question, I know the answer is to replace the 305 with a 350, LT or LS, this may be a future option as he works and saves up for it.

Now on to the question! As i stated, it is a 1987 which has the center bolt valve covers. We need to pull the motor to redo gaskets, clean it up and whatnot. While it is out we are going to put headers on it and thinking about new heads and mild cam to go with the Elderbrock performer intake and Holley 600 carb that are on it now. Will 1986 heads bolt and work on a 1987 block? I know the valve covers will be different, but that's not a big deal. I also think that we would have to replace the intake because they changed the angle of the bolts between '86 and '87. It looks like all of the parts we are looking at will also work on a 350 as well so when the time comes we should be able to take all of these parts of and transfer to a 350 when he is ready.

Any thoughts would be appreciated.

 

Welcome to the forum!

Heads should fit, but you'll have to buy a pre-87 intake. However, since you asked for any thoughts. . .

If you're going through the trouble of pulling the 305, swapping heads, swapping intake, installing headers, etc. etc. you'd make better use of your money to just put all that effort into a 350 block from the start instead of doing all this, slapping it back in, then doing it all over again in a year or two.
You can get a basic 87+ long block from Jegs for $1,800 (which is probably what you'd have in your replacement heads and intake on your original idea) then put your current intake on, get some headers, and go. https://www.jegs.com/i/JEGS/059/8758/10002/-1

No it's not a high-performance engine, but it gives you many more options in the future (without having to pull it all out again) for around the same price.

OR, alternative #2 - just get the 305 running right as-is. Sounds like it needs a new fuel pump & filter and it'd probably stay running.

 

What size valves were you going with ?

 

Hmmm... all of the motors I saw on Jegs and Summit were way more expensive! Never stumbled upon these truck motors. By the time we redo all of the gaskets, seals, cleaning and prep work I have a feeling we would be into for half the cost of the new motor. Plus the extra 100 horsepower and probably at least double the torque. Damn it, probably going to have to put a new motor in it! I see a note that this motor does not have provisions for a mechanical fuel pump, the current setup is the PITA pump in the fuel tank (which we already replaced) and a mechanical on the block. Would I add an additional electric pump?

Thanks for the input and sharing that link.

 

Glad to help brainstorm!

As for the fuel pump, the pics on the website seem to show that the block has the spot for a mechanical, but if it doesn't then you can try it with just the in-tank pump (and a regulator). A lot of folks just run the in tank pump. If you have fuel delivery issues or vapor-locking with that set-up you can switch to a more powerful single electric pusher pump with a regulator (that's what I run). Either way, it's not a difficult issue to get around.

 

the truck block may show the provision for the block mounted fuel pump but until you get it you won't know if it has been bored for a fuel pump rod.

the '87 vin h heads should be fine for a mild performance 305. they are better than the '88 up TBI heads. likely no different than the '86 heads. until you post the head model #s it's a guess.

I'd consider running what you've got with maybe a mild cam. upgrade to a 350 later if you want. that truck 350 will probably be a flat tappet motor anyway, a step down from the roller 305 you have in the valve train department.

save that money now until you've got some miles and confidence in the rest of the vehicle's pieces/parts (especially the trans).

 

thats a small flat tappet camshaft and likely poor flowing swirlport heads. You won't see 100hp or double torque. Though the 45 ci will be an upgrade from the 305, it won't be near that.
Not saying 'do not buy' this long block but it isn't exactly a barn storming engine over the current engine. Depends on what you decide the plan for the car it. The roller cam in the 305 is much better than the flat tappet but the crate does instantly give you more displacement.
GL on the project.

 

For less than $100 more, you can get a Vortec crate engine with a roller cam, better heads, probably better pistons, etc. It'd take a Vortec pattern intake, but it'd be a much better engine for not much more money. https://www.jegs.com/i/JEGS/059/0282/10002/-1

 

my opinion its better to learn on the old engine thats about to be replaced anyways, make mistakes on that engine. Rather than trying to install a brand new fresh engine and making novice mistakes on the new engine.

I would let him learn on the old engine, work on it, study it, eventually some critical overlook will cause a failure- but you were just going to throw it away anyways