Help with my chevy

[Kelvin]

Hi all

My 305 turned up early and is now in the way in my garage, but hey it's here. Speaking to people i have been told that i need to get shot of my iron heads and invest in some alli ones. Does this sound right ? I'm looking for around 300 bhp.

How can i tell if my engine is low compression. I have looked on the http://www.mortec.com/castnum.htm site to try and get some info but it doesnt say what it was first put in.

I'm in need of a g/box, i'm running a normal sierra diff, would it be better to get a 4 speed and keep it on the cam or enjoy the 5 speed ? and what make should i be looking for ?

I've looked around real steals site but not sure what it is im after

Thanx for any replies

Kelvin

[Kelvin]

Hi again,

Sorry forgot, it has a mechanical pump, should i use this or a leccy one.

Come on wilf i know its a chevy but there are some answers in there somewhere

Ta again

Kelvin

[Martin427]

Hi Kelvin,
I have a std Chevy 350 with a Tremek 5 speed box.
I also have a Sierra diff.
I have not run the car much as I'm just going for my SVA re-test, only 60 miles or so.
The 5 speed is great and I'd recommend it.
I have an electric pump as I want to keep all the power under the hood going to the rear wheels}> }> }>

I've blown my budget so will stick with the std heads and work on some more power later.

Martin

[Kelvin]

Thanx martin,

My set-up is much the same as yours so i might aswell go with the 5 speed

Kelvin

[mikey]

If yo give me your head numbers I will try to work your compression ratio out for you. That is if the mortec site gives cylinder head combustion chamber volumes. It will also assume you have got standard pistons which have on average 1.5cc valve reliefs.
Regards.
Mike.

[Kelvin]

Thanx mikey

I haven't taken the cam covers off yet, but im gonna have to to get them chromed, the person who i bought it off (who i do know personally) said that there are flat top pistons in there.

I was wondering if there are any other sites which might give me an insite into what the motor was put in. I will probably end up putting the motor in as is (as it was rebuilt 20 hrs ago) and see how i get on, then if i get no hp end up changing the heads with alli ones. Might give realsteal a ring tomorrow to get a price.

Kelvin

[Miket]

Kelvin

Contact smax@smax.co.uk or www.fastco.uk.com for ally heads, it will save you stacks of dosh.

Miket

[dave]

Hi Martin.
That leccy pump you have is powered by your alternator....which sucks power from your engine, it's swings and roundabouts mate.

[Bowtie]

I got my self a 1988 305 for reasons I already mentioned on this board. The 305 is infamous and some would call you stupid if you try to build it for power. I think I know why after some serious investigation.

The 350 will always outperform the 305 if you stick to the power for money ratio. There is less after market performance parts for the 305 and they cost the same or more than the parts for the 350.

The bigger displacement of the 350 will outperform the 305 so that a fairly stock 350 will deliver the same power as a tuned 305. So more money is needed to tune the 305 than the 350 to a certain power level. The weight of the 305 and the 350 is also almost the same.

So given the above fact why would anyone want to stick with the 305? The best argument would probably be fuel consumption. If you only aim at some 200 to 300 hp, low fuel consumption and comfortable driving characteristics then the 305 could be a really nice alternative to the 350. The long stroke and small bore 305 will give you good low-end torque (for its displacement) and a TBI injection (hidden under an open element air cleaner to get the retro look of a carb engine) can decrease fuel consumption even more and make the engine run smother and more reliable than with a traditional carb.

If the above characteristics are what you want then it could be worth spending some money on the 305. If not then save the money and buy a 350 instead (305 and 350 share a lot of parts so some parts used to build the 305 can later on be reused on a 350).

What is reasonable to spend on a 305 then? It probably depends on what you have to start with. There are several different kinds of 305 like the LB9 TPI, L03 TBI or 4bbl LE9 and LF3. I got a L03 ‘H’ and my heads are really bad. Good thing is that the block is prepared to take a roller cam. Same heads but a stock roller cam is found on the L03 ‘E’. The LB9 got better heads and a roller cam and so on.

What you generally need is better heads, cam, exhaust manifold and intake manifold (in that order). The bottom can be left as it is (if the engine already got flat top pistons).

Remember that we can’t spend too much money on upgrade parts so we have to find high performance alternatives that don’t cost a fortune. Here are some alternatives I am thinking of for my 305:

Heads:
LB9 Cast iron ported for reasonable flow
L98 Aluminum (58cc no EGR) good flow and same comp as stock.
Edelbrock Performer (60cc max .450 lift) better flow but less comp than stock.
Vortecs (64cc no EGR) great flow but much less comp than stock, has to be milled for maximum performance but cant be reused on a 350 if milled.

Cam:
Stock from LT1

Exhaust manifold:
Stock from Corvette
Any Chevy small block headers

Intake manifold:
Stock aluminium (same as on 350) ported for better flow
Vortecs (no EGR) great flow
Any aftermarket intake manifold with an adapter plate for the TBI

I also got a list of very expensive parts that would do the job even better but I then think it is better to buy a new 350-crate engine for that kind of money...

Good luck with your engine modifications / Bowtie

[Kelvin]

Hi all,

So should i stay with the mechanical one ??

Kelvin