Modifying a stock 327 (300hp)
01-08-2013, 02:19 PM
#21
Race Director
Little Mouse: If I were to go with the Hooker Super Comps (1 3/4 primary), would that make peak power arrive at a much later RPM?
Based on the suggestions of many (including some of the guys on this post) I will likely bring it into the shop sometime next month for:
1) The distributor recurve
2) Lower gear ratio of 3.55 or 3.73 (I am still undecided...not quite sure by how much the 3.73 will increase the RPMs at idle and whether I'd be stressing the engine too much if I were to take it on the freeway).
3) & 4) Edelbrock Performer EPS Intake Manifold + Headers (long tube or shortys?)
I'd like to do the intake manifold and headers now and then wait to do the cylinders heads and camshaft...what do you think?
Lastly, how would my 3 speed automatic react to a change to something like a 3.73 gear ratio?
Thanks All!
Based on the suggestions of many (including some of the guys on this post) I will likely bring it into the shop sometime next month for:
1) The distributor recurve
2) Lower gear ratio of 3.55 or 3.73 (I am still undecided...not quite sure by how much the 3.73 will increase the RPMs at idle and whether I'd be stressing the engine too much if I were to take it on the freeway).
3) & 4) Edelbrock Performer EPS Intake Manifold + Headers (long tube or shortys?)
I'd like to do the intake manifold and headers now and then wait to do the cylinders heads and camshaft...what do you think?
Lastly, how would my 3 speed automatic react to a change to something like a 3.73 gear ratio?
Thanks All!
01-08-2013, 05:32 PM
#22
Little Mouse: If I were to go with the Hooker Super Comps (1 3/4 primary), would that make peak power arrive at a much later RPM?
Based on the suggestions of many (including some of the guys on this post) I will likely bring it into the shop sometime next month for:
1) The distributor recurve
2) Lower gear ratio of 3.55 or 3.73 (I am still undecided...not quite sure by how much the 3.73 will increase the RPMs at idle and whether I'd be stressing the engine too much if I were to take it on the freeway).
3) & 4) Edelbrock Performer EPS Intake Manifold + Headers (long tube or shortys?)
I'd like to do the intake manifold and headers now and then wait to do the cylinders heads and camshaft...what do you think?
Lastly, how would my 3 speed automatic react to a change to something like a 3.73 gear ratio?
Thanks All!
Based on the suggestions of many (including some of the guys on this post) I will likely bring it into the shop sometime next month for:
1) The distributor recurve
2) Lower gear ratio of 3.55 or 3.73 (I am still undecided...not quite sure by how much the 3.73 will increase the RPMs at idle and whether I'd be stressing the engine too much if I were to take it on the freeway).
3) & 4) Edelbrock Performer EPS Intake Manifold + Headers (long tube or shortys?)
I'd like to do the intake manifold and headers now and then wait to do the cylinders heads and camshaft...what do you think?
Lastly, how would my 3 speed automatic react to a change to something like a 3.73 gear ratio?
Thanks All!
01-18-2013, 03:34 PM
#23
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First Steps...
1) What size tires would I need to switch to if I went with 3.73 rear axle ratio?
2) What type of perfomance air cleaner would you guys recommend for the '68 Vette (327 c.i.)?
3) Looking for a good set of long tube headers that will fit my automatic TH400 transmission....any ideas? Instructions for Hooker Competition Headers says it does not fit Turbo 400 applications---oddly enough the instructions for Hooker's Super Competition Headers does not list this same incompatibility...
4) Lastly, I am really thinking of upgrading the intake manifold at the same time I do the distributor curve, headers and gears...anybody have opinions or experience with Edelbrock's Performer EPS and if it'll be worth the upgrade over my stock manifold??
2) What type of perfomance air cleaner would you guys recommend for the '68 Vette (327 c.i.)?
3) Looking for a good set of long tube headers that will fit my automatic TH400 transmission....any ideas? Instructions for Hooker Competition Headers says it does not fit Turbo 400 applications---oddly enough the instructions for Hooker's Super Competition Headers does not list this same incompatibility...
4) Lastly, I am really thinking of upgrading the intake manifold at the same time I do the distributor curve, headers and gears...anybody have opinions or experience with Edelbrock's Performer EPS and if it'll be worth the upgrade over my stock manifold??
01-18-2013, 09:47 PM
#24
Burning Brakes
1) What size tires would I need to switch to if I went with 3.73 rear axle ratio?
2) What type of perfomance air cleaner would you guys recommend for the '68 Vette (327 c.i.)?
3) Looking for a good set of long tube headers that will fit my automatic TH400 transmission....any ideas? Instructions for Hooker Competition Headers says it does not fit Turbo 400 applications---oddly enough the instructions for Hooker's Super Competition Headers does not list this same incompatibility...
4) Lastly, I am really thinking of upgrading the intake manifold at the same time I do the distributor curve, headers and gears...anybody have opinions or experience with Edelbrock's Performer EPS and if it'll be worth the upgrade over my stock manifold??
2) What type of perfomance air cleaner would you guys recommend for the '68 Vette (327 c.i.)?
3) Looking for a good set of long tube headers that will fit my automatic TH400 transmission....any ideas? Instructions for Hooker Competition Headers says it does not fit Turbo 400 applications---oddly enough the instructions for Hooker's Super Competition Headers does not list this same incompatibility...
4) Lastly, I am really thinking of upgrading the intake manifold at the same time I do the distributor curve, headers and gears...anybody have opinions or experience with Edelbrock's Performer EPS and if it'll be worth the upgrade over my stock manifold??
1) If you change the rear tire height to a much taller aspect you will negate all of the effect of re-gearing the car to lower gears, why change rear tires ? Keep what you have now to see the real differance, later if tires are needed you can fine tune the height to adjust some interstate rpm lower. If you go with a 3.55 - do not consider changing tire height.
2) Any cold-air system is your best bet always, any lack of that just remember to use what fits with no smaller than a 14"X3" filter. (colder than "under the hood" air temps always increase power and lower your chance of detonation or needing a higher octane fuel).
3) Allways use a longtube header, and in your case do not go larger than 1 5/8's primary tube diameter. A great freeflowing exhaust behind these is paramount !
4) See the new edit below.
The ignition recalibration is essential, but check to see if your distributor has excessive wear in it also, (don't need a great curve but with inconsistent timing). The advice giving about your Qjet could'nt be more accurate, if a Qjet professional rebuilds it he will set it up with differant specs than stock and right for your combo. He will also bush the throttle shafts if need be - that is not normally included with someone else's bench rebuild.
Just these listed steps will make you think it's an L79
Last edited by 68post; 01-18-2013 at 10:04 PM. Reason: added an "s" , guess where
01-18-2013, 09:58 PM
#25
Burning Brakes
An EPS manifold is not able to mount a spreadbore type carb such as a Qjet. Need a differant option, and I spoke too soon, sorry!
EDIT: Weiand does show a couple of manifolds that would work (idle to 5500), or you can always use a regular performer intake. If you change heads and cam later - you may want to wait on the intake and then consider an #7104 Performer RPM which is compatibale,(IF you are using 3.73 gears).
EDIT: Weiand does show a couple of manifolds that would work (idle to 5500), or you can always use a regular performer intake. If you change heads and cam later - you may want to wait on the intake and then consider an #7104 Performer RPM which is compatibale,(IF you are using 3.73 gears).
Last edited by 68post; 01-18-2013 at 10:26 PM. Reason: editing
01-18-2013, 11:45 PM
#26
Le Mans Master
Do yourself a favor and change the torque converter... It will do more for acceleration then anything else you do.... Ideally a converter swap and 3.55s would be good for a revving little 327 build but... If you want to keep the 3.08s for good highway cruising, you need to do a good converter, it wont raising your highway rpms much but it will make a big difference when you hammer it.
As for the 327 build, we just finished my Dads #s matching 327/350hp rebuild. We tried a few tricks but honestly(224/230 cam, ported the 461 camel humps/3 angle VJ), its still a turd.... Stock ram horn manifolds and side pipes just kill it.... not to mention the stock 585 cfm holley and stock aluminum intake.....
You're smart for switching to headers/real exhaust system and a good intake setup. Definitely keep the compression around 10.0 with iron heads or 10.5ish with aluminum heads, a decent cam and spin the crap out of it... Good aluminum heads will go a long way. Some AFR 180s or even 195s would really wake it up..
As for the 327 build, we just finished my Dads #s matching 327/350hp rebuild. We tried a few tricks but honestly(224/230 cam, ported the 461 camel humps/3 angle VJ), its still a turd.... Stock ram horn manifolds and side pipes just kill it.... not to mention the stock 585 cfm holley and stock aluminum intake.....
You're smart for switching to headers/real exhaust system and a good intake setup. Definitely keep the compression around 10.0 with iron heads or 10.5ish with aluminum heads, a decent cam and spin the crap out of it... Good aluminum heads will go a long way. Some AFR 180s or even 195s would really wake it up..