355 TPI HP Estimate - Third Generation F-Body Message Boards

dredre08 · 11-14-2010, 10:35 PM

What's up guys, I'm posting because I finally got a replacement for this beat up piece of s*** 305 that's in my 86 T/A, I've been looking for a 350 for about a year now and finally got one. Now im not trying make my car a racer or anything, just wanted to upgrade my 305 with something with a little more power. I have got my hands on a freshly rebuilt 350 and I was wondering could you guys give me a rough estimate of horsepower that I should be getting from my new motor. Ok here's the specs of the engine from the guy who rebuilt it. It's a 4 bolt main, It has #624 cly heads Bronze liners,milled 010 3 angle valve job 010 block,trw 4.030 pistons,hastings single moly rings,clevite bearings HV oil pump fel pro gaskets, Double roller timing chain,valves adjusted oil primed, and it has a 272/468 erson cam, and I plan on using the stock tpi intake that's on my 305(already have 350 knock sensor,22lb injecters, and 350 ecm ready for the swap) and its going to bolted up to my 700r4...... So could any one give me a rough estimate of h/p dat I should be getting with the specs that I provided (that's all I know about it, and that's the info dat was on the receipt that I was givin) sorry if I wrote anything down incorrectly I'm a engine novice.......

Also if I add some headers how much horsepower am I looking at??

So basically I wanna know could u guys give me a horsepower estimate without headers and with headers??

vetteoz · 11-14-2010, 10:58 PM

Quote:

Originally Posted by dredre08

here's the specs of the engine

...
So could any one give me a rough estimate of h/p dat I should be getting with the specs that I provided

You have a 355 TPI with a little more compression ( also depends on pistons and no info on those)
Nothing you mention above changes performance except for cam and need more info on that
Heads are nothing special
http://www.chevelles.com/forums/show...91&postcount=4

dredre08 · 11-14-2010, 11:06 PM

Vetteoz ,like I said I'm a engine novice, let me see if I can dig any more info on it but that's all I really know as of right now.... and not really looking for performance just something a little more powerful then that stock 305.

dredre08 · 11-14-2010, 11:15 PM

Vetteoz just read your link, Im almost crying in the inside... might be investing in some new heads later own down the road.

vetteoz · 11-14-2010, 11:32 PM

Quote:

Originally Posted by dredre08

Vetteoz ,like I said I'm a engine novice, let me see if I can dig any more info on it.

To calc compression ( higher compression = more power ) need to know size of dish ( cc ) in piston

Need to know duration @ 0.050 on cam; not advertised duration #
( 276 ) you posted
Should have a spec sheet from cam maker if new cam installed

dredre08 · 11-15-2010, 12:04 AM

Ok I looked at cam specs, it says 224/224 as duration(not advertised) can't find anything on pistons as of yet

Fast355 · 11-15-2010, 12:22 AM

Quote:

Originally Posted by dredre08

What's up guys, I'm posting because I finally got a replacement for this beat up piece of s*** 305 that's in my 86 T/A, I've been looking for a 350 for about a year now and finally got one. Now im not trying make my car a racer or anything, just wanted to upgrade my 305 with something with a little more power. I have got my hands on a freshly rebuilt 350 and I was wondering could you guys give me a rough estimate of horsepower that I should be getting from my new motor. Ok here's the specs of the engine from the guy who rebuilt it. It's a 4 bolt main, It has #624 cly heads Bronze liners,milled 010 3 angle valve job 010 block,trw 4.030 pistons,hastings single moly rings,clevite bearings HV oil pump fel pro gaskets, Double roller timing chain,valves adjusted oil primed, and it has a 272/468 erson cam, and I plan on using the stock tpi intake that's on my 305(already have 350 knock sensor,22lb injecters, and 350 ecm ready for the swap) and its going to bolted up to my 700r4...... So could any one give me a rough estimate of h/p dat I should be getting with the specs that I provided (that's all I know about it, and that's the info dat was on the receipt that I was givin) sorry if I wrote anything down incorrectly I'm a engine novice.......

Also if I add some headers how much horsepower am I looking at??

So basically I wanna know could u guys give me a horsepower estimate without headers and with headers??

You basically have a 1985 Corvette L98 with a double roller chain and non computer friendly cam upgrade. 224 @ .050 is too much duration for a stock chipped, stock TPI runner, crappy flowing 624 head setup. I doubt it will have the power of your stock 305. The stock 85 L98 was something around 230 HP, put that in a F-car with a weaker computer program and more restrictive intake/exhaust piping and you will be down around 215-220 HP.

dredre08 · 11-15-2010, 12:27 AM

Fast 355, So what do you suggest I do to improve this... what would be a good but not to expensive set of heads to replace these??

dredre08 · 11-15-2010, 12:37 AM

Quote:

Originally Posted by Fast355

You basically have a 1985 Corvette L98 with a double roller chain and non computer friendly cam upgrade. 224 @ .050 is too much duration for a stock chipped, stock TPI runner, crappy flowing 624 head setup. I doubt it will have the power of your stock 305. The stock 85 L98 was something around 230 HP, put that in a F-car with a weaker computer program and more restrictive intake/exhaust piping and you will be down around 215-220 HP.

Fast 355, So what do you suggest I do to improve this... what would be a good but not to expensive set of heads to replace these??

Air_Adam · 11-15-2010, 01:18 AM

Whats the casting number on the heads on your 305? Some of them actually work quite well on a 350. If you have the #416 heads, like an original '86 should have, then those are a good choice for a 350.

vetteoz · 11-15-2010, 05:44 AM

Quote:

Originally Posted by dredre08

,. what would be a good but not to expensive set of heads to replace these??

The link I posted above had some common alternative iron heads that would be better than yours
The smaller size chambers will also give you some compression

Orr89RocZ · 11-15-2010, 09:09 AM

Quote:

Vetteoz just read your link, Im almost crying in the inside... might be investing in some new heads later own down the road.

Do it. On a budget, try to find some regular iron L98 heads and just smooth out the ports alittle with a grinder. Smooth out the casting flaws. They can support a decent amount of power with alittle bit of work.

Even some of the 305 TPI based heads would give you some compression but the intake valve could be smaller so it will hurt flow alittle bit. A mild 350 may like the smaller valve however. A set of those can be found for free or up to 100-150 bucks. Do a clean up and replace valvesprings and you'll be ok for a mild build. Ported TPI or aftermarket TPI bolt ons will really wake it up with that sized cam. Tune it to match it should run ok.

Vortec heads are great bang for buck but you need vortec base to work with them. Thats another 450 bucks which is ridiculous if you ask me. You can go vortec HSR for almost 150 more and make tons more power...better suited to the cams rpm range.

dredre08 · 11-15-2010, 10:00 AM

Quote:

Originally Posted by Fast355

You basically have a 1985 Corvette L98 with a double roller chain and non computer friendly cam upgrade. 224 @ .050 is too much duration for a stock chipped, stock TPI runner, crappy flowing 624 head setup. I doubt it will have the power of your stock 305. The stock 85 L98 was something around 230 HP, put that in a F-car with a weaker computer program and more restrictive intake/exhaust piping and you will be down around 215-220 HP.

Man I'm

f***** furious rite now the guy I bought this motor from (according to wat u guys told me) flat out lied to me!!!!!!!!, I just texted him he said with these specs I should be getting a 9.5 to 1 compression ratio and the I should be getting roughly 300 HP ( a little m

ore or a little less) now this is totally impossible with these specs correct??????

See I told this guy I was only a 19 year engine novice and that I wasn't looking for a race car just something more powerful then my 305 something near 300 HP and I trusted this guy, and now it sounds like I got totally screwed..... so basically I'm nowhere near 300 h/p

dredre08 · 11-15-2010, 10:11 AM

Quote:

Originally Posted by Orr89RocZ

Do it. On a budget, try to find some regular iron L98 heads and just smooth out the ports alittle with a grinder. Smooth out the casting flaws. They can support a decent amount of power with alittle bit of work.

Even some of the 305 TPI based heads would give you some compression but the intake valve could be smaller so it will hurt flow alittle bit. A mild 350 may like the smaller valve however. A set of those can be found for free or up to 100-150 bucks. Do a clean up and replace valvesprings and you'll be ok for a mild build. Ported TPI or aftermarket TPI bolt ons will really wake it up with that sized cam. Tune it to match it should run ok.

Vortec heads are great bang for buck but you need vortec base to work with them. Thats another 450 bucks which is ridiculous if you ask me. You can go vortec HSR for almost 150 more and make tons more power...better suited to the cams rpm range.

Orr89 so if I get vortec heads what all would I need aftermarket and what could I use from my stock tpi (a kid is on a budget lol) I found these vortecs on jeggs there not that bad in price are they any good???? Like I said I'm a complete novice!!!!

http://www.jegs.com/i/GM%20Performan...0002/-1?CT=999

Orr89RocZ · 11-15-2010, 12:10 PM

Vortec heads need vortec TPI base. Stock runners/plenum will bolt to it but wont help power production since they will limit the air flow.

Quote:

It's a 4 bolt main, It has #624 cly heads Bronze liners,milled 010 3 angle valve job 010 block,trw 4.030 pistons,hastings single moly rings,clevite bearings HV oil pump fel pro gaskets, Double roller timing chain,valves adjusted oil primed, and it has a 272/468 erson cam, and I plan on using the stock tpi intake that's on my 305(already have 350 knock sensor,22lb injecters, and 350 ecm ready for the swap) and its going to bolted up to my 700r4..

If its a flat top piston and 76cc head, then you would be at 9.1 to 1 compression. that aint bad for iron headed motor although you could probably go as high as 9.8-10.0 to 1 with that cam on good gas with good tuning.

If they flow as much as an Iron L98 head or close to it i can see you matching the power of an L98 and possibly exceeding it with the larger cam. Problem is cam may be too big for the intake system and give up alot of low end performance for little top end peak gain. Combined with a better TPI on top, it should pick up, but it needs a good tune.

dredre08 · 11-15-2010, 12:51 PM

Quote:

Originally Posted by Orr89RocZ

If its a flat top piston and 76cc head, then you would be at 9.1 to 1 compression. that aint bad for iron headed motor although you could probably go as high as 9.8-10.0 to 1 with that cam on good gas with good tuning.

If they flow as much as an Iron L98 head or close to it i can see you matching the power of an L98 and possibly exceeding it with the larger cam. Problem is cam may be too big for the intake system and give up alot of low end performance for little top end peak gain. Combined with a better TPI on top, it should pick up, but it needs a good tune.

Wouldn't porting the runners help with the my problem with the cam (if they were the flat top piston and a 74cc head) am u on the right track, and if that dies help how much does that usually cost to the tpi runners ported

Orr89RocZ · 11-15-2010, 01:42 PM

cant really port the stock runners..they are thin cast or extruded and not much can be done with them. You'd need to look into aftermarket runners to get larger tubes.

dredre08 · 11-15-2010, 02:00 PM

Quote:

Originally Posted by Orr89RocZ

cant really port the stock runners..they are thin cast or extruded and not much can be done with them. You'd need to look into aftermarket runners to get larger tubes.

Ok I found out what I have the head is 72 cc and its a flat top piston 4 valve relief.... now say I just get a whole new after market tpi system with these heads and piston and my cam wat could I expect

vetteoz · 11-15-2010, 03:24 PM

Quote:

Originally Posted by dredre08

.... now say I just get a whole new after market tpi system with these heads and piston and my cam wat could I expect

Like Orr89RocZ said; forget the TPI based system and buy a HSR ( cost less )
Better all round performance and good base for future mods

Orr89RocZ · 11-15-2010, 03:29 PM

I would hope with a tune it would be close to 325hp on motor or so. I mean a full bolt ons TPI car will dyno 250whp and run low low 13's in a 3450lb raceweight. A cam of that size should give it some more power although not all that much due to heads/intake rpm limitations. I would hope to see 275whp and possible high 12's but that may be abit optimistic. I know these cars respond well to 1.6 rockers on stock cams/stock heads, so abit more duration and lift with a tune should net 15whp IMO..atleast.

dredre08 · 11-15-2010, 05:20 PM

Quote:

Originally Posted by vetteoz

Like Orr89RocZ said; forget the TPI based system and buy a HSR ( cost less )
Better all round performance and good base for future mods

Well I was trying to keep that stock look but if I do that it. seems like ill just be in the same boat as I was with my 305 tpi and that we be like buying a motor for nothing.... so I guess I should go with the hsr plus it looks better and ill just store tpi away for a rainy day.....

so how much does a hsr cost, I seem to can't find a consistent price online..... and is dis a easy swap????l

dredre08 · 11-15-2010, 05:36 PM

Quote:

Originally Posted by Orr89RocZ

Do it. On a budget, try to find some regular iron L98 heads and just smooth out the ports alittle with a grinder. Smooth out the casting flaws. They can support a decent amount of power with alittle bit of work.

Even some of the 305 TPI based heads would give you some compression but the intake valve could be smaller so it will hurt flow alittle bit. A mild 350 may like the smaller valve however. A set of those can be found for free or up to 100-150 bucks. Do a clean up and replace valvesprings and you'll be ok for a mild build. Ported TPI or aftermarket TPI bolt ons will really wake it up with that sized cam. Tune it to match it should run ok.

Vortec heads are great bang for buck but you need vortec base to work with them. Thats another 450 bucks which is ridiculous if you ask me. You can go vortec HSR for almost 150 more and make tons more power...better suited to the cams rpm range.

Ok orr I think I might go with your idea of the hsr, let me first ask do I need vortecs heads with this?... and if u don't what could I expect from the hsr on my crappy 624 heads, and paired with my cam and piston???

And how much do they usually run because I can't seem to find one online

vetteoz · 11-15-2010, 06:40 PM

Quote:

Originally Posted by dredre08

I guess I should go with the hsr
so how much does a hsr cost, .

New from Summit
http://www.summitracing.com/parts/WND-7540/
http://www.summitracing.com/parts/HLY-534-185/
+ some custom fuel lines and fittings for engine bay hookup

Always good ( better ) deals going in 3rd Gen parts
http://www.thirdgen.org/techboard/en...-ram-fast.html (FS: Stealth Ram, FAST FI, and more!)

I bought a bare HSR with fuel rails for $200 on there last month

Quote:

Originally Posted by dredre08

.. and is dis a easy swap????l

A lot easier to work on than TPI intake
HSR swap how to and parts list
http://www.thirdgen.org/techboard/al...r-install.html (?'s regaurding the HSR install in GMHTP(fuel related))

dredre08 · 11-15-2010, 09:34 PM

Ok I must say that I'm totally sold on the hsr..... I've done research on the hsr and it fits right in my budget , I also did research on my 624 heads and yea they are as crappy like all u say but that's all I got right now and plus the motor is completely assembled just waiting on a intake..... I have one last question, with the specs of my engine and adding the hsr what can I expect horsepower wise????

Orr89RocZ · 11-15-2010, 10:14 PM

It should make a good bit more. My HSR swap on a stock motor helped alot. A mild cam to take advantage of the rpms the HSR can support should show further increase in power, even with factory iron heads.

dredre08 · 11-16-2010, 07:10 PM

ok thanks for all your help guys, i deffiently am going to get this holley stealth ram, and all i need is the manifolds, throttle body, and fuel rails, and use my tpi wiring harness and all that right??? and do i use the 22lb injecters are will i need bigger because i was looking at the kit that comes with everything and it comes with 30lb injecters.

vetteoz · 11-16-2010, 08:22 PM

Quote:

Originally Posted by dredre08

all i need is the manifolds, throttle body, and fuel rails, and use my tpi wiring harness and all that right???.

You don't " need " the new TB up front.
Stock TB will work OK until you have some $$$

Orr89RocZ · 11-16-2010, 11:22 PM

22lb stockers will work fine unless they are clogged or leaking from being old. Stock TB will work fine, but it may hit the holley fuel rails...simple fix is to grind the bracket on the TB where it hits. You will know where when you install it all and see it. May not happen since you have an 86 TPI motor? Bracket/linkage was different on that year I believe compared to my 89 so you may not have a problem.

Some info on my swap.
http://www.thirdgen.org/techboard/al...ealth-ram.html (My Holley Stealth Ram swap)

dredre08 · 11-17-2010, 10:43 AM

Quote:

Originally Posted by Orr89RocZ

Do it. On a budget, try to find some regular iron L98 heads and just smooth out the ports alittle with a grinder. Smooth out the casting flaws. They can support a decent amount of power with alittle bit of work.

Even some of the 305 TPI based heads would give you some compression but the intake valve could be smaller so it will hurt flow alittle bit. A mild 350 may like the smaller valve however. A set of those can be found for free or up to 100-150 bucks. Do a clean up and replace valvesprings and you'll be ok for a mild build. Ported TPI or aftermarket TPI bolt ons will really wake it up with that sized cam. Tune it to match it should run ok.

Vortec heads are great bang for buck but you need vortec base to work with them. Thats another 450 bucks which is ridiculous if you ask me. You can go vortec HSR for almost 150 more and make tons more power...better suited to the cams rpm range.

Ok Orr I didn't realize what u had said at first about vortec hsr, I think I have come up with what I'm going to do.... I am going to get me a set of vortec heads and get the hsr vortec manifolds to go with it, I'm not in a rush since this isn't my daily driver just my project, I would rather wait and just save up the money and make it a faster car and get more use out of my cam

So if I swap my crappy 624 heads for these vortec heads http://www.jegs.com/i/GM%20Performan...0002/-1?CT=999

Get the holly stealth ram vortec in combo with my cam (224/224 duration)

Flat top piston 4 valve relief

Throw some headers on

How close would I be to 300 h/p with this set up and what kinda of compression could I expect

1989GTATransAm · 11-17-2010, 12:34 PM

Those heads are only rated for .475" max lift out of the box.

vetteoz · 11-17-2010, 06:07 PM

Quote:

Originally Posted by 1989GTATransAm

Those heads are only rated for .475" max lift out of the box.

http://www.thirdgen.org/techboard/te...ortec-lt4.html (5.7 Vortec LT4 Hotcam Install Pics and Information)

dredre08 · 11-17-2010, 08:00 PM

Quote:

Originally Posted by 1989GTATransAm

Those heads are only rated for .475" max lift out of the box.

so what would the lift on my heads need to be to work optimal with my cam....(sorry guys engine novce over here)

vetteoz · 11-17-2010, 09:31 PM

Quote:

Originally Posted by dredre08

so what would the lift on my heads need to be to work optimal with my cam...

Valve lift you have is determined by the cam itself.
Can only be changed by changing cam (or using rockers with different ratio )
You stated above your cam has .468" lift so that is the lift you have now

dredre08 · 11-17-2010, 10:43 PM

Quote:

Originally Posted by vetteoz

Valve lift you have is determined by the cam itself.
Can only be changed by changing cam (or using rockers with different ratio )
You stated above your cam has .468" lift so that is the lift you have now

I'm confused

my lift is .468 and the heads I want are .475.... do the lift of the came and max lift on heads have to match exactly
??

1989GTATransAm · 11-17-2010, 10:56 PM

You are fine. You just don't want to exceed the .475" lift. You are at .468" so you have a little wiggle room. When I put a cam in my Vortec 383HTE motor for my Tahoe I cheated a little and went with .480" lift. Working just fine with around 30,000 miles on it.

dredre08 · 11-17-2010, 11:11 PM

Well thank everybody for there help...... just one last question could some one please give me a rough estimate of possible horsepower and compression with my future set up

Vortec heads (the ones in the link)
Flat top piston
Cam 224/224 duration
Holly stealth RAM intake
Headers

dredre08 · 11-18-2010, 03:38 PM

Anybody???

VincentZ28 · 11-18-2010, 05:27 PM

330-345rwhp

dredre08 · 11-29-2010, 12:17 PM

Hey guys kno this posting is kinda if old but with a set of 217 casting number heads be worth the time????

dredre08 · 11-29-2010, 10:43 PM

Does anyone have a opinion on the 217 crate engine heads being used with my set up

dredre08 · 12-02-2010, 11:55 PM

Any input on the 217 heads with my setup???? Please!!!! I need to know before I buy