305 build advice. Any and all advice is appreciated!

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gotyourgoat

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smokin' 305
Friends don't let friends rebuild 305s. You can throw all the parts at you want but nothing replaces... displacement.
They never should have put these engines in trucks.
At least Eric's truck is a 2x, but still not worth it imo.

Sorry I know it's not what you want to hear...
Honestly surprised it took this long for that answer. Usually it's about the only response apart from the question 'why would anybody build a 305?' Along with some other disparaging remarks.

It is true though after all the time, work and money put into a 305 it's just not going to be any better than a basic 350. I say that having a modded 305 in my truck.:eek:
 

shiftpro

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Honestly surprised it took this long for that answer. Usually it's about the only response apart from the question 'why would anybody build a 305?' Along with some other disparaging remarks.

It is true though after all the time, work and money put into a 305 it's just not going to be any better than a basic 350. I say that having a modded 305 in my truck.:eek:
Yes the more pain received the better the lesson learned.
 

Ewhitaker0020

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Honestly surprised it took this long for that answer. Usually it's about the only response apart from the question 'why would anybody build a 305?' Along with some other disparaging remarks.

It is true though after all the time, work and money put into a 305 it's just not going to be any better than a basic 350. I say that having a modded 305 in my truck.:eek:

Alright you all have convinced me. I will plan on buying a 350 and having it rebuilt. It'll cost about the same as the 305, but will be much better.
 

gotyourgoat

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Accessories won't swap over like a 305/350 swap though. Just go ls3, super simple. ;)
 

82sbshortbed

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Okay, now I've change my mind again. I'm going with the 454 BB engine. Don't try to change my mind!

Yup that's what I did

You must be registered for see images attach


On the garage floor.

You won't regret it!

:burnout:

Here come the gratuitous burnouts :hahano:
 

1987 GMC Jimmy

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It looks like this is pretty much settled, but I will say that the compression ratio for the LE9 you have should be 9.5:1. Something like that. I’m sure you’d see a poop compression ratio in the 8s or even 7s with some of the many throwaway heads that came on the 305, but that wouldn’t be the case on the LE9, L69, or LB9 running 416 or 601 heads.

I think the value of the 305 really comes into play if it’s what you already have, either a healthy engine or a good rebuild candidate. Anything you can get out of a 305, the 350 can do the same and perform better, but I don’t think the 305 is anything to scoff at if you bored and stroked it out to 334, ported and polished the heads to 1.94/1.6 (2.02 is probably a stretch), upgraded the cam, new valve springs, aluminum intake (more for ease of assembly than performance), headers, carb recalibration, and went with a traditional HEI with a hotter coil and an emphasis on being able to recalibrate the spark curve in order to get around the 305’s inherent timing sensitivities. I think you could have a truck that had around 375 RWHP, give or take.

400 RWHP is probably the absolute max that’s attainable on a normally driveable, pump gas 305, and that 400 is much easier and a good bit cheaper to attain with a 350/383 stroker. That’s what I’d do.

Big blocks are great, I love them, and in the proper roles, I’d build them, but you talked about being budget friendliness in your initial post. Initially considering the 305 makes me think you want maybe not a daily but a regular driver. The 305 is as economical as they come for old school V8s. Full-size passenger cars with the 305 can get MPG numbers in the low 20s if that tells you anything. The 396, 454, or whatever isn’t that. Maybe the gap between a built 350/383 and a run of the mill, unchoked 454 isn’t huge, but expect half the economy you’re getting with the 305, assuming you average around 17-19 mpg right now, hope for a hair better, and prepare for slightly worse. My other question is would you not be tempted to add onto the 454’s base performance capabilities? I know I would be. I don’t know what kind of decrease in economy that would entail, and it may not be much, but if you’re young, just starting out, have a family, these are factors worth considering. I guess it depends on what you plan to do with the truck and how often you plan to use it.
 

Ewhitaker0020

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It looks like this is pretty much settled, but I will say that the compression ratio for the LE9 you have should be 9.5:1. Something like that. I’m sure you’d see a poop compression ratio in the 8s or even 7s with some of the many throwaway heads that came on the 305, but that wouldn’t be the case on the LE9, L69, or LB9 running 416 or 601 heads.

I think the value of the 305 really comes into play if it’s what you already have, either a healthy engine or a good rebuild candidate. Anything you can get out of a 305, the 350 can do the same and perform better, but I don’t think the 305 is anything to scoff at if you bored and stroked it out to 334, ported and polished the heads to 1.94/1.6 (2.02 is probably a stretch), upgraded the cam, new valve springs, aluminum intake (more for ease of assembly than performance), headers, carb recalibration, and went with a traditional HEI with a hotter coil and an emphasis on being able to recalibrate the spark curve in order to get around the 305’s inherent timing sensitivities. I think you could have a truck that had around 375 RWHP, give or take.

400 RWHP is probably the absolute max that’s attainable on a normally driveable, pump gas 305, and that 400 is much easier and a good bit cheaper to attain with a 350/383 stroker. That’s what I’d do.

Big blocks are great, I love them, and in the proper roles, I’d build them, but you talked about being budget friendliness in your initial post. Initially considering the 305 makes me think you want maybe not a daily but a regular driver. The 305 is as economical as they come for old school V8s. Full-size passenger cars with the 305 can get MPG numbers in the low 20s if that tells you anything. The 396, 454, or whatever isn’t that. Maybe the gap between a built 350/383 and a run of the mill, unchoked 454 isn’t huge, but expect half the economy you’re getting with the 305, assuming you average around 17-19 mpg right now, hope for a hair better, and prepare for slightly worse. My other question is would you not be tempted to add onto the 454’s base performance capabilities? I know I would be. I don’t know what kind of decrease in economy that would entail, and it may not be much, but if you’re young, just starting out, have a family, these are factors worth considering. I guess it depends on what you plan to do with the truck and how often you plan to use it.


I was joking about adding a big block. I'm just going to stick with the 305 or 350 which I'm leaning way towards the 350 just because the ceiling is much higher than what the 305 can attain. I'm going to look for a 95 and later vortec head 350 from a truck and rebuild it for my truck.

If there was a big difference in the price of rebuilding a 305 vs a 350 then I would be tempted to rebuild my 305, but since they're going to cost roughly the same I might as well go for the 350. In another thread they're talking me into going with a later model vortec 350 because the heads are so much better than the stock heads on my engine.
 

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